How To Use The IEEEtran LaTeX Class Manual

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JOURNAL OF L

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How to Use the IEEEtran L

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X Class

Michael Shell, Member, IEEE

(Invited Paper)

Abstract—This article describes how to use the IEEEtran class

with L

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X to produce high quality typeset papers that are suit-

able for submission to the Institute of Electrical and Electronics

Engineers (IEEE). IEEEtran can produce conference, journal

and technical note (correspondence) papers with a suitable choice

of class options. This document was produced using IEEEtran

in journal mode.

Index Terms—Class, IEEEtran, L

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X, paper, style, template,

typesetting.

I. INTRODUCTION

WITH a recent IEEEtran class file, a computer running

L

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X, and a basic understanding of the L

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X language,

an author can produce professional quality typeset research

papers very quickly, inexpensively, and with minimal effort.

The purpose of this article is to serve as a user guide of

IEEEtran L

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X class and to document its unique features and

behavior.

This document applies to version 1.8b and later of IEEEtran.

Prior versions do not have all of the features described here.

IEEEtran will display the version number on the user’s console

when a document using it is being compiled. The latest version

of IEEEtran and its support files can be obtained from IEEE’s

web site [1], or CTAN [2]. This latter site may have some

additional material, such as beta test versions and files related

to non-IEEE uses of IEEEtran. See the IEEEtran homepage

[3] for frequently asked questions and recent news about

IEEEtran.

Complimentary to this document are the files1bare_con

f.tex,bare_jrnl.tex,bare_jrnl_comsoc.tex,bare_

conf_compsoc.tex,bare_jrnl_compsoc.tex and bare_

jrnl_transmag.tex, which are “bare bones” example (tem-

plate) files of a conference, journal, IEEE Communications

Society journal, IEEE Computer Society conference, IEEE

Computer Society journal and IEEE TRANSACTIONS ON

MAGNETICS paper, respectively. Authors can quickly obtain

a functional document by using these files as starters for their

own work. A more advanced example featuring the use of

Manuscript created February 25, 2002; revised August 26, 2015. This work

was supported by the IEEE. This work is distributed under the L

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Public License (LPPL) ( http://www.latex-project.org/ ) version 1.3. A copy

of the LPPL, version 1.3, is included in the base L

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X documentation of all

distributions of L

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X released 2003/12/01 or later. The opinions expressed

here are entirely that of the author. No warranty is expressed or implied. User

assumes all risk.

See http://www.michaelshell.org/ for current contact information.

1Note that it is the convention of this document not to hyphenate command

or file names and to display them in typewriter font. Within such

constructs, spaces are not implied at a line break and will be explicitly carried

into the beginning of the next line. This behavior is not a feature of IEEEtran,

but is used here to illustrate computer commands verbatim.

optional packages along with more complex usage techniques,

can be found in bare_adv.tex.

It is assumed that the reader has at least a basic working

knowledge of L

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X. Those so lacking are strongly encouraged

to read some of the excellent literature on the subject [4]–[6].

In particular, Tobias Oetiker’s The Not So Short Introduction

to L

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X 2ε[5], which provides a general overview of working

with L

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X, and Stefan M. Moser’s How to Typeset Equations

in L

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X[6], which focuses on the formatting of IEEE-style

equations using IEEEtran’s IEEEeqnarray commands, are both

available for free online.

General support for L

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in the internet newsgroup comp.text.tex. There is also a

searchable list of frequently asked questions about L

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X [7].

Please note that the appendices sections contain information

on installing the IEEEtran class file as well as tips on how to

avoid commonly made mistakes.

II. CLASS OPTIONS

There are a number of class options that can be used to

control the overall mode and behavior of IEEEtran. These are

specified in the traditional L

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X way. For example,

\documentclass[9pt,technote]{IEEEtran}

is used with correspondence/brief/technote papers. The various

categories of options will now be discussed. For each category,

the default option is shown in bold. The user must specify an

option from each category in which the default is not the one

desired. The various categories are totally orthogonal to each

other—changes in one will not affect the defaults in the others.

A. 9pt, 10pt, 11pt, 12pt

There are four possible values for the normal text size. 10pt

is used by the vast majority of papers. Notable exceptions are

technote papers, which use 9pt text and the initial submissions

to some conferences that use 11pt.

Be aware that IEEE Computer Society publications use

“PostScript” (i.e., “big point”, bp) point sizes (i.e., 72bp =

1in) rather than the traditional typesetters’ point (i.e., 72.27pt

= 1in). Also, “10pt” IEEE Computer Society journal papers

actually use a slightly smaller, 9.5bp, font size (probably to

compensate for the slightly wider nature of the Palatino font).

IEEEtran will automatically tweak the selected font size as

needed depending on the mode.

0000–0000/00$00.00 c

2015 Michael Shell

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B. draft, draftcls, draftclsnofoot, final

IEEEtran provides for three draft modes as well as the

normal final mode. The draft modes provide a larger (double)

line spacing to allow for editing comments as well as one

inch margins on all four sides of the paper. The standard draft

option puts every package used in the document into draft

mode. With most graphics packages, this has the effect of

disabling the rendering of figures. If this is not desired, one

can use the draftcls option instead to yield a draft mode that

will be confined within the IEEEtran class so that figures will

be included as normal. draftclsnofoot is like draftcls, but does

not display the word “DRAFT” along with the date at the

foot of each page. Both draft and draftclsnofoot modes imply

draftcls (which is a subset of the other two). When using one

of the draft modes, most users will also want to select the

onecolumn option.

C. conference, journal, technote, peerreview, peerreviewca

IEEEtran offers five major modes to encompass conference,

journal, correspondence (brief/technote) and peer review pa-

pers. Journal and technote modes will produce papers very

similar to those that appear in many IEEE TRANSACTIONS

journals. When using technote, most users should also select

the 9pt option. The peerreview mode is much like the journal

mode, but produces a single-column cover page (with the

title, author names and abstract) to facilitate anonymous peer

review. The title is repeated (without the author names or

abstract) on the first page after the cover page.2Papers using

the peer review options require an \IEEEpeerreviewmaket

itle command (in addition to and after the traditional \make

title) to be executed at the place the cover page is to end—

usually just after the abstract. This command will be silently

ignored with the non-peerreview modes. See the bare template

files for an example of the placement of this command. The

peerreviewca mode is like peerreview, but allows the author

name information to be entered and formatted as is done

in conference mode (see Section IV-B2 for details) so that

author affiliation and contact information is more visible to

the editors.

1) Conference Mode Details: Conference mode makes a

number of significant changes to the way IEEEtran behaves:

•The margins are increased as the height of the text is

reduced to about 9.25in. In particular, the bottom margin

will become larger than that of the top as the IEEE wants

extra clearance at the bottom. The text height will not be

exactly 9.25in, but will vary slightly with the normal font

size to ensure an integer number of lines in a column.

•Headings and page numbers are not displayed in the

headers or footers. This, coupled with symmetric hori-

zontal margins, means that there will not be a noticeable

difference between the one and two sided options.

•The \author text is placed within a tabular environment

to allow for multicolumn formatting of author names and

2A blank page may be inserted after the cover page when using the twoside

(duplex printing) option so that the beginning of the paper does not appear

on the back side of the cover page.

affiliations. Several commands are enabled to facilitate

this formatting (see Section IV-B2 for details).

•The spacing after the authors’ names is reduced. So is

the spacing around the section names.

•The special paper notice (if used) will appear between the

author names and the title (not after as with journals).

•The figure captions are centered.

•The following commands are intentionally disabled: \t

hanks,\IEEEPARstart,\IEEEbiography,\IEEEb

iographynophoto,\IEEEpubid,\IEEEpubidadjco

l,\IEEEmembership, and \IEEEaftertitletext. If

needed, they can be reenabled by issuing the command:

\IEEEoverridecommandlockouts.

•Various reminder (related to camera ready work) and

warning notices are enabled.

When using conference mode, most users will also want to

equalize the columns on the last page (see Section XIV).

D. comsoc, compsoc, transmag

These mutually exclusive options invoke special modes by

which IEEEtran produces the format of the publications of the

IEEE Communications Society, IEEE Computer Society and

IEEE TRANSACTIONS ON MAGNETICS, respectively. Neither

of these are enabled by default.

1) Comsoc Mode: Comsoc mode only affects the math font

so that it will more closely match the Times Roman main text.

Either Michael Sharpe’s freely available newtxmath package

[8] (version 1.451, July 28, 2015 or later is recommended)

or the commercial MathTime [9] math fonts (as mtpro2.sty,

mt11p.sty or mathtime.sty) are acceptable. Under comsoc

mode, if one of these packages has not been loaded by the

user at the start of the document, IEEEtran will attempt to

enforce their use based on what is available on the system.

The recommended loading procedure and order for newtx-

math is:

\usepackage[T1]{fontenc} % optional

\usepackage{amsmath}

\usepackage[cmintegrals]{newtxmath}

\usepackage{bm} % optional

where the cmintegrals option, which IEEEtran sets as a default

upon loading newtxmath, is needed to obtain the specific style

of integral symbol used by the IEEE Communications Society.

The optional bm package [10] provides for selective bold

math. Be aware that the AMS Math amssymb.sty package [11]

is not needed and should not be loaded as that functionality is

built into and provided by newtxmath as well as MathTime.

Also, do not load the newtxtext.sty package as doing so would

alter the main text font.

a) Comsoc Conference Mode: Comsoc conference pa-

pers are, at present, done the same way as traditional confer-

ence papers (bare_conf.tex) and so no additional example

file is required. Unless specifically instructed otherwise by

the conference that is being submitting to, do not invoke the

comsoc option with conference papers.

2) Compsoc Mode: Notable compsoc mode format features

include:

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•the default text font is changed from Times Roman

to Palatino/Palladio (non-conference compsoc modes

only);

•revised margins;

•Arabic section numbering;

•enabling of the \IEEEcompsocitemizethanks and \I

EEEcompsocthanksitem commands to provide for the

\thanks (first footnote) itemized list used for author

affiliations;

•enabling of the \IEEEtitleabstractindextext com-

mand to provide for single column abstract and index

terms (see Section V);

•various other styling changes (most of which are only

applicable under the non-conference compsoc modes)

such as the use of: a sans serif (Helvetica) font for titles,

headings, etc.; a ruled line above the first footnote area;

left aligned reference labels; etc.

a) Compsoc Conference Mode: IEEEtran follows the

guidelines for IEEE Computer Society conference papers.

Perhaps surprisingly, this format nullifies many of the unique

features of compsoc journals and is not so much different

from traditional conference mode. However, Arabic section

numbering is retained. It should be mentioned that Scott

Pakin’s IEEEconf L

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X class [12] also produces this format.

Be aware that many IEEE Computer Society conferences use

the traditional conference format and compsoc mode should

not be used with them.

3) Transmag Mode: For the transmag mode:

•The text within \author should be entered as the long

form under conference mode;

•enabling of the \IEEEtitleabstractindextext com-

mand to provide for single column abstract and index

terms (see Section V);

•\IEEEauthorrefmark will produce arabic author affil-

iation symbols;

•subsection and subsubsection headings and/or their spac-

ings are slightly different;

•a smaller, bold font than normal is used for the title.

The transmag mode (as well as the standard journal mode)

is also acceptable for submission to IEEE Magnetics Letters.

Authors who wish to have their figures and tables appear at

the end of the paper can use the endfloat.sty [13] package to

achieve this.

E. letterpaper, a4paper, cspaper

IEEEtran fully supports both the US letter (8.5in ×11in)

and A4 (210mm ×297mm) paper sizes. Since the IEEE

primarily uses US letter, authors should usually select the

letterpaper option before submitting their work to the IEEE—

unless told otherwise (typically by conferences held outside

the United States). Changing the paper size in the standard

journal and conference modes will not alter the typesetting of

the document—only the margins will be affected. In particular,

documents using the a4paper option will have reduced side

margins (A4 is narrower than US letter) and a longer bottom

margin (A4 is longer than US letter). For both cases, the top

margins will be the same and the text will be horizontally

centered.

For the compsoc conference and draft modes, it is the

margins that will remain constant, and thus the text area size

will vary, with changes in the paper size.

The cspaper option is the special “trim” paper size (7.875in

×10.75in) used in the actual publication of IEEE Computer

Society journals. Under compsoc journal mode, this option

does not alter the typesetting of the document. Authors should

invoke this option only if requested to do so by the editors of

the specific journal they are submitting to.

Note that authors should ensure that all post-processing

(PS, PDF, etc.) uses the same paper specification as the .tex

document. Problems here are by far the number one reason

for incorrect margins. See Appendix B for more details.

For the special cspaper size, be aware that although IEEE-

tran will automatically configure the correct paper dimensions

for pdfL

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X’s PDF mode (which it does for all paper sizes),

dvips (the application used for DVI to PS conversion) systems

will not recognize the special “ieeecs” paper unless there is

such an entry in dvips’ config.ps configuration file:

% Special paper size for the IEEE Computer Society J

ournals

@ ieeecs 7.875in 10.75in

@+ ! %%DocumentPaperSizes: ieeecs

@+ %%BeginPaperSize: ieeecs

@+ /setpagedevice where

@+ { pop << /PageSize [567 774] >> setpagedevice }

@+ if

@+ %%EndPaperSize

Most modern PS to PDF conversion software will correctly

handle such custom paper sizes if a different specific paper

size is not explicitly requested for the conversion process.

F. oneside, twoside

These options control whether the layout follows that of

single sided or two sided (duplex) printing. Because the side

margins are normally centered, the main notable difference is

in the format of the running headings.

G. onecolumn, twocolumn

These options allow the user to select between one and

two column text formatting. Since the IEEE always uses two

column text, the onecolumn option is of interest only with

draft papers.

H. romanappendices

IEEEtran defaults to numbering appendices alphabetically

(e.g., A, B, etc.). Invoke this option to get Roman numbering.

I. captionsoff

Invoking this option will inhibit the display of captions

within figures and tables. This is done in a manner that

preserves the operation of \label within \caption. This

option is intended for journals, such as IEEE TRANSACTIONS

ON POWER ELECTRONICS (TPE), that require figures and

tables to placed, captionless, on pages of their own at the

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end of the document. Such figure placement can be achieved

with the help of the endfloat.sty package [13]:

\usepackage[nomarkers]{endfloat}

Note that the TPE has other unusual formatting requirements

that also require the draftclassnofoot and onecolumn options

as well as the insertion of page breaks (\newpage) just prior

to the first section as well as the bibliography. Such commands

can be enabled conditionally via the \ifCLASSOPTIONcapt

ionsoff conditional (Section III-A).

J. nofonttune

IEEEtran normally alters the default interword spacing to

be like that used in IEEE publications. The result is text that

requires less hyphenation and generally looks more pleasant,

especially for two column text. The nofonttune option will

disable the adjustment of these font parameters. This option

should be of interest only to those who are using fonts

specifically designed or modified for use with two column

work.

III. THE CLASSINPUT, CLASSOPTION AND

CLASSINFO CONTROLS

IEEEtran offers three catagories of special commands that

allow information to be passed between the class file and the

user’s document:

•CLASSINPUTs are inputs that provide a way to cus-

tomize the operation of IEEEtran by overriding some of

the default settings (at the time IEEEtran is loaded);

•CLASSOPTIONs which are outputs that allow for condi-

tional compilation based on which IEEEtran class options

have been selected;

•CLASSINFOs which are outputs that allow the user a

way to access additional information about the IEEEtran

runtime environment.

A. CLASSINPUTs

The available CLASSINPUTs include: \CLASSINPUTbase

linestretch which sets the line spacing of the document;

\CLASSINPUTinnersidemargin which sets the margin at

the inner (binding) edge; \CLASSINPUToutersidemargin

which sets the margin at the outer edge; \CLASSINPUTtopt

extmargin which sets the top margin; \CLASSINPUTbotto

mtextmargin which sets the bottom margin. Of course, such

parameters can be set via the traditional L

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sidemargin,\topmargin, etc.). However, the advantage of

of using the CLASSINPUT approach is that it allows IEEEtran

to adjust other internal parameters and perform any additional

calculations as needed. For example, setting the side margins

in L

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X requires a careful setting of \oddsidemargin,\e

vensidemargin and \textwidth taking into consideration

the paper size and whether or not duplex (two-sided) printing

is being used.

To invoke a CLASSINPUT, just define the relavant CLASS-

INPUT as desired prior to the loading of IEEEtran. For

example,

\newcommand{\CLASSINPUTinnersidemargin}{17mm}

\documentclass{IEEEtran}

will yield a document that has 17mm side margins—if only

one of the innerside/outerside (or toptext/bottomtext) margin

pair is specified, IEEEtran will assume the user wants sym-

metric side (or top/bottom) margins and will set both values

of the relavant pair to the (single) user specified value.

IEEEtran uses the fixed values of 12pt and 0.25in for \h

eadheight and \headsep, respectively. The position of

the header can be altered after IEEEtran is loaded, without

changing the margins as long as the sum of \topmargin,

\headheight and \headsep is preserved. For example, the

header can be shifted upwards 0.2in using:

\addtolength{\headsep}{0.2in}

\addtolength{\topmargin}{-0.2in}

Likewise, \footskip, which has a default value of 0.4in, can

easily be changed to alter the position of the footer within the

bottom margin.

When using \CLASSINPUTbaselinestretch, IEEEtran

will automatically “digitize” \textheight so that an integer

number of lines will fit on a page (as is done in the draft

modes). Digitization is not done when the top or bottom

margins are set via CLASSINPUTs. Users are cautioned that

using CLASSINPUT controls can result in documents that

are not compliant with the IEEE’s standards. The intended

applications include: (1) conferences or societies that have

unusual formatting requirements; (2) producing copies with

nonstandard margins such as when binding for personal use;

and (3) non-IEEE related work.

B. CLASSOPTIONs

CLASSOPTIONs are primarily T

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are automatically set based on which IEEEtran options are

being used. Thus, for example, a construct such as

\ifCLASSOPTIONconference

\typeout{in conference mode}

\else

\typeout{not in conference mode}

\fi

can be used to provide for conditional code execution. Please

note that, as mentioned in Section II-B, the draft and draft-

clsnofoot options imply draftcls. So, most users will want to

test \ifCLASSOPTIONdraftcls for detecting the draft

modes.

For the document’s point size options, \CLASSOPTIONp

tis defined as a macro that expands to the numerical part

of the selected point value (e.g., 9, 10, 11 or 12). For the

paper size options, \CLASSOPTIONpaper will be a macro

that contains the paper specification (e.g., letter, a4). To use

these as conditionals will require a string macro comparison:

\newcommand{\myninestring}{9}

\ifx\CLASSOPTIONpt\myninestring

\typeout{document is 9pt}

\fi

Users should treat the CLASSOPTIONs as being “read-only”

and not attempt to manually alter their values because IEEE-

tran uses them internally as flags to determine which options

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have been selected—changing these flags will likely result in

improper formatting.

C. CLASSINFOs

The available CLASSINFOs include the \ifCLASSINFOp

df conditional which works much like Heiko Oberdiek’s if-

pdf.sty package [14] to indicate if PDF output (from pdfL

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is in effect:

\ifCLASSINFOpdf

\typeout{PDF mode}

\fi

IEEEtran.cls also provides the lengths \CLASSINFOnorma

lsizebaselineskip, which is the \baselineskip of the

normalsize font, and \CLASSINFOnormalsizeunitybaseli

neskip, which is the \baselineskip of the normalsize font

under unity \baselinestetch.

Finally, there are the string macros (these are not condition-

als or lengths) \CLASSINFOpaperwidth and \CLASSINF

Opaperheight which contain the paper dimensions in their

native specifications including units (e.g., 8.5in, 22mm, etc.).

As with CLASSOPTIONs, users should not attempt to alter

the CLASSINFOs.

IV. THE TITLE PAGE

The parts of the document unique to the title area are created

using the standard L

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command is called, the author must declared all of the text

objects which are to appear in the title area.

A. Paper Title

The paper title is declared like:

\title{A Heuristic Coconut-based Algorithm}

in the standard L

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except for words such as a, an, and, as, at, but, by, for, in, nor,

of, on, or, the, to and up, which are usually not capitalized

unless they are the first or last word of the title. Line breaks

(\\) may be used to equalize the length of the title lines. Do

not use math or other special symbols in the title.

B. Author Names

The name and associated information is declared with the

\author command. \author behaves slightly differently

depending on the document mode.

1) Names in Journal/Technote Mode: A typical \author

command for a journal or technote paper looks something like

this:

\author{Michael˜Shell,˜\IEEEmembership{Member,˜IEEE,

} John˜Doe,˜\IEEEmembership{Fellow,˜OSA,} and˜Jane˜D

oe,˜\IEEEmembership{Life˜Fellow,˜IEEE}%

\thanks{Manuscript received January 20, 2002; revise

d August 26, 2015. This work was supported by the IE

EE.}%

\thanks{M. Shell was with the Georgia Institute of T

echnology.}}

The \IEEEmembership command is used to produce the

italic font that indicates the authors’ IEEE membership status.

The \thanks command produces the “first footnotes.” Be-

cause the L

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paragraphs3, authors will have to use a separate \thanks

for each paragraph. However, if needed, regular line breaks

(\\) can be used within \thanks. In order to get proper line

breaks and spacing, it is important to correctly use and control

the spaces within \author. Use nonbreaking spaces (˜) to

ensure that name/membership pairs remain together. A minor,

but easy, mistake to make is to forget to prevent unwanted

spaces from getting between commands which use delimited

({}) arguments. Note the two %which serve to prevent the

code line break on lines ending in a }from becoming an

unwanted space. Such a space would not be ignored as an

end-of-line space because, technically, the last \thanks is

the final command on the line. “Phantom” spaces like these

would append to the end of the last author’s name, causing

the otherwise centered name line to shift very slightly to the

left.

2) Names in Conference Mode: The author name area

is more complex when in conference mode because it also

contains the authors’ affiliations. For this reason, when in

conference mode, the contents of \author{} are placed

into a modified tabular environment. The commands \IE

EEauthorblockN{} and \IEEEauthorblockA{} are also

provided so that it is easy to correctly format the author names

and affiliations, respectively. For papers with three or less

affiliations, a multicolumn format is preferred:

\author{\IEEEauthorblockN{Michael Shell}

\IEEEauthorblockA{School of Electrical and\\

Computer Engineering\\

Georgia Institute of Technology\\

Atlanta, Georgia 30332--0250\\

Email: mshell@ece.gatech.edu}

\and

\IEEEauthorblockN{Homer Simpson}

\IEEEauthorblockA{Twentieth Century Fox\\

Springfield, USA\\

Email: homer@thesimpsons.com}

\and

\IEEEauthorblockN{James Kirk\\

and Montgomery Scott}

\IEEEauthorblockA{Starfleet Academy\\

San Francisco, California 96678-2391\\

Telephone: (800) 555--1212\\

Fax: (888) 555--1212}}

Use \and to separate the affiliation columns. The columns

will automatically be centered with respect to each other and

the side margins.

If there are more than three authors and/or the text is too

wide to fit across the page, use an alternate long format:

\author{\IEEEauthorblockN{Michael Shell\IEEEauthorre

fmark{1}, Homer Simpson\IEEEauthorrefmark{2}, James K

irk\IEEEauthorrefmark{3}, Montgomery Scott\IEEEautho

rrefmark{3} and Eldon Tyrell\IEEEauthorrefmark{4}}

\IEEEauthorblockA{\IEEEauthorrefmark{1}School of Ele

ctrical and Computer Engineering\\

Georgia Institute of Technology, Atlanta, Georgia 30

332--0250\\

Email: mshell@ece.gatech.edu}

\IEEEauthorblockA{\IEEEauthorrefmark{2}Twentieth Cen

tury Fox, Springfield, USA\\

Email: homer@thesimpsons.com}

3Although IEEEtran.cls does support it, the standard classes do not.

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\IEEEauthorblockA{\IEEEauthorrefmark{3}Starfleet Aca

demy, San Francisco, California 96678-2391\\

Telephone: (800) 555--1212, Fax: (888) 555--1212}

\IEEEauthorblockA{\IEEEauthorrefmark{4}Tyrell Inc.,

123 Replicant Street, Los Angeles, California 90210

--4321}}

The \IEEEauthorrefmark{} command will generate a foot-

note symbol corresponding to the number in its argument. Use

this to link the author names to their respective affiliations. It is

not necessary prevent spaces from being between the \IEEEa

uthorblock’s because each block starts a new group of lines

and L

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lines.

3) Names in Compsoc Journal Mode: One unique feature

of IEEE Computer Society journals is that author affiliations

are formatted in an itemized list within the first (\thanks)

footnote. In compsoc mode, IEEEtran provides a special form

of \thanks,\IEEEcompsocitemizethanks, to obtain this

effect:

\author{Michael˜Shell,˜\IEEEmembership{Member,˜IEEE,

} John˜Doe,˜\IEEEmembership{Fellow,˜OSA,} and˜Jane˜D

oe,˜\IEEEmembership{Life˜Fellow,˜IEEE}%

\IEEEcompsocitemizethanks{\IEEEcompsocthanksitem M.

Shell is with the Georgia Institute of Technology.

\IEEEcompsocthanksitem J. Doe and J. Doe are with An

onymous University.}%

\thanks{Manuscript received January 20, 2002; revise

d August 26, 2015.}}

Within \IEEEcompsocitemizethanks,\IEEEcompsoctha

nksitem works like \item to provide a bulleted affiliation

group. To facilitate dual compilation, in non-compsoc mode,

IEEEtran treats \IEEEcompsocitemizethanks as \thanks

and sets \IEEEcompsocthanksitem to generate a line break

with indentation. However, this is not entirely satisfactory as

IEEE Computer Society journals place the author affiliations

before the “manuscript received” line while traditional IEEE

journals use the reverse order. If correct dual compilation is

needed, the CLASSOPTION conditionals can be employed to

swap the order as needed.

4) Names in Compsoc Conference Mode: Names in comp-

soc conference mode are done in the same way as traditional

conference mode.

5) Names in Transmag Journal Mode: IEEE TRANSAC-

TIONS ON MAGNETICS papers typically use the conference

long format for author names, but try to keep each name and

address pair on one line and without any email addresses or

phone numbers. Also, \thanks is available under transmag

journal mode even though the names are entered much like

the long format under conference mode. See the file bare_

jrnl_transmag.tex for an example of author entry under

transmag mode.

C. Running Headings

The running headings are declared with the \markboth{

}{} command. The first argument contains the journal name

information and the second contains the author name and paper

title. For example:

\markboth{Journal of Quantum Telecommunications,˜Vol

.˜1, No.˜1,˜January˜2025}{Shell \MakeLowercase{\text

it{et al.}}: A Novel Tin Can Link}

Note that because the text in the running headings is automat-

ically capitalized, the \MakeLowercase{} command must be

used to obtain lower case text. The second argument is used

as a page heading only for the odd number pages after the

title page for two sided (duplex) journal papers. This page is

such an example. Technote papers do not utilize the second

argument. Conference papers do not have running headings,

so \markboth{}{} has no effect when in conference mode.

Authors should not put any name information in the headings

(if used) of anonymous peer review papers.

D. Publication ID Marks

Publication ID marks can be placed on the title page of

journal and technote papers via the \IEEEpubid{} command:

\IEEEpubid{0000--0000/00\$00.00˜\copyright˜2015 IEEE

}

Although authors do not yet have a valid publication ID at the

time of paper submission, \IEEEpubid{} is useful because it

provides a means to see how much of the title page text area

will be unavailable in the final publication. This is especially

important in technote papers because, in some journals, the

publication ID space can consume more than one text line. If

\IEEEpubid{} is used, a second command, \IEEEpubidad

jcol must be issued somewhere in the second column of the

title page. This is needed because L

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X resets the text height

at the beginning of each column. \IEEEpubidadjcol “pulls

up” the text in the second column to prevent it from blindly

running into the publication ID.

Publication IDs are not to be placed by the author on camera

ready conference papers so \IEEEpubid{} is disabled in

conference mode. Instead the bottom margin is automatically

increased by IEEEtran when in conference mode to give the

IEEE room for such marks at the time of publication. In draft

mode, the publisher ID mark will not be printed at the bottom

of the titlepage, but room will be cleared for it.

Publication ID marks are perhaps less important with comp-

soc papers because IEEE Computer Society journals place the

publisher ID marks within the bottom margin so as not to

affect the amount of page space available for text.

E. Special Paper Notices

Special paper notices, such as for invited papers, can be

declared with:

\IEEEspecialpapernotice{(Invited Paper)}

Special paper notices in journal and technote papers appear

between the author names and the main text. The title page

of this document has an example. For conference papers, the

special paper notice is placed between the title and the author

names.

Much more rarely, there is sometimes a need to gain access

to the space across both columns just above the main text.

For instance, a paper may have a dedication [15]. IEEEtran

provides the command \IEEEaftertitletext{} which can

be used to insert text or to alter the spacing between the title

area and the main text:

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\IEEEaftertitletext{\vspace{-1\baselineskip}}

Authors should be aware that IEEEtran carefully calculates

the spacing between the title area and main text to ensure that

the main text height of the first page always is equal to an

integer number of normal sized lines (unless the top or bottom

margins have been overridden by CLASSINPUTs). Failure to

do this can result in underfull vbox errors and paragraphs

being “pulled apart” in the second column of the first page

if there isn’t any rubber lengths (such as those around section

headings) in that column. The contents of \IEEEaftertitle

text{} are intentionally allowed to bypass this “dynamically

determined title spacing” mechanism, so authors may have to

manually tweak the height (by a few points) of the \IEEEa

ftertitletext{} contents (if used) to avoid an underfull

vbox warning.

V. ABSTRACT AND INDEX TERMS

The abstract is generally the first part of a paper after \m

aketitle. The abstract text is placed within the abstract

environment:

\begin{abstract}

We propose ...

\end{abstract}

Math, special symbols and/or citations should generally not

be used in abstracts.4

Journal and technote papers also have a list of key words

(index terms) which can be declared with:

\begin{IEEEkeywords}

Broad band networks, quality of service, WDM.

\end{IEEEkeywords}

To obtain a list of valid keywords from the IEEE, just send a

blank email to keywords@ieee.org. A list of IEEE Computer

Society approved keywords can be obtained at http://www.

computer.org/mc/keywords/keywords.htm. Do not use math or

special symbols in the keywords.

The IEEE Computer Society and IEEE TRANSACTIONS ON

MAGNETICS formats present a difficulty in that compsoc and

transmag journal (but not compsoc conference) papers place

the abstract and index terms sections in single column format

just below the author names, but the other IEEE formats place

them in the first column of the main text before the first

section. To handle this, IEEEtran offers a command, \IEEEt

itleabstractindextext, that is to be declared before \ma

ketitle, and whose single argument holds the text/sections

that are to appear in single column format after the author

names:

\IEEEtitleabstractindextext{%

\begin{abstract}

We propose ...

\end{abstract}

\begin{IEEEkeywords}

Broad band networks, quality of service, WDM.

\end{IEEEkeywords}}

4That said, if it is permitted or required, be aware that in order to preserve

the distinction between constructs such as vector and scalar forms, IEEEtran

defaults to using non-bold math within the abstract. However, bold math better

matches the bold text font used for the abstract text. If a bold math font is

desired, just issue a \boldmath command at the start of the abstract.

To facilitate dual compilation, IEEEtran provides another

command, \IEEEdisplaynontitleabstractindextext,

which will “become” whatever was declared in \IEEEtitl

eabstractindextext when in non-compsoc, non-transmag

or conference mode (as compsoc conferences use the same

placement for the abstract and index terms as traditional

conferences do). That is to say, the abstract and index terms

sections can be automatically “teleported’ to the appropriate

place they need to be depending on the document mode. \IE

EEdisplaynontitleabstractindextext should typically

be placed just after \maketitle (and before \IEEEpeerre

viewmaketitle if used).

VI. SECTIONS

Sections and their headings are declared in the usual L

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fashion via \section,\subsection,\subsubsection,

and \paragraph. In the non-compsoc modes, the numbering

for these sections is in upper case Roman numerals, upper case

letters, Arabic numerals and lower case letters, respectively.

In compsoc mode, Arabic numerals are used exclusively for

(sub)section numbering.

The \paragraph section is not allowed for technotes or

compsoc conferences as these generally are not permitted to

have such a deep section nesting depth. If needed, \paragra

ph can be restored by issuing the command \setcounter{

secnumdepth}{4} in the document preamble.

Note that IEEE Computer Society journals (but not con-

ferences!) are unusual in that they raise the very first section

(the introduction) heading above the start of the text. IEEEtran

provides a command to produce this effect:

\IEEEraisesectionheading{\section{Introduction}\labe

l{sec:introduction}}

This command is not intended for any use other than the

introduction section in compsoc journal mode. Note the need

to keep any \label that is to refer to the section immediately

after \section in the above as \IEEEraisesectionheadi

ng puts \section within a raised box.

A. Initial Drop Cap Letter

The first letter of a journal paper is a large, capital, oversized

letter which descends one line below the baseline. Such a

letter is called a “drop cap” letter. The other letters in the first

word are rendered in upper case. This effect can be accurately

produced using the IEEEtran command \IEEEPARstart{}{

}. The first argument is the first letter of the first word, the

second argument contains the remaining letters of the first

word. The drop cap of this document was produced with:

\IEEEPARstart{W}{ith}

Note that some journals will also render the second word in

upper case—especially if the first word is very short. For more

usage examples, see the bare_jrnl.tex example file.

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VII. CITATIONS

Citations are made with the \cite command as usual.

IEEEtran will produce citation numbers that are individually

bracketed in IEEE style. (“[1], [5]” as opposed to the more

common “[1, 5]” form.) The base IEEEtran does not sort or

produce compressed “ranges” when there are three or more

adjacent citation numbers. However, IEEEtran pre-defines

some format control macros to facilitate easy use with Donald

Arseneau’s cite.sty package [16]. So, all an author has to do

is to call cite.sty:

\usepackage{cite}

and the adjacent citation numbers will automatically be sorted

and compressed (ranged) IEEE style. (Of course, multiple

adjacent citations should always all be declared within a

single \cite, comma separated, for this to work.) Invoke

cite.sty’s noadjust option to prevent an unwanted leading space

from occurring should a citation ever need to be enclosed in

parenthesis.

One complication in compsoc mode is that the IEEE

Computer Society does not compress, but does sort, adjacent

citation numbers. Version 4.0 and later of cite.sty provides a

nocompress option that disables compression, but preserves

sorting. Thus,

\ifCLASSOPTIONcompsoc

% requires cite.sty v4.0 or later (November 2003)

\usepackage[nocompress]{cite}

\else

\usepackage{cite}

\fi

can be used with universal applicability.

Note that, if needed (e.g., next to a non-punctuation, non-

space character), cite.sty’s \cite command will automatically

add a leading space. i.e., “(\cite{mshell01})” will become

like “( [1])”. If this behavior is not desired, use the cite

package’s noadjust option (cite.sty V3.8 and later) which will

turn off the added spaces:

\usepackage[noadjust]{cite}

\cite also allows for an optional note (e.g., \cite[Th.

7.1]{mshell01}). If the \cite with note has more than

one reference, the note will be applied to the last of the listed

references. It is generally desirable that if a note is given, only

one reference should be listed in that \cite.

VIII. EQUATIONS

Equations are created using the traditional equation envi-

ronment:

\begin{equation}

\label{eqn_example}

x = \sum\limits_{i=0}^{z} 2^{i}Q

\end{equation}

which yields

x=

z

X

i=0

2iQ. (1)

Use the displaymath environment instead if no equation

number is desired. When referring to equations, articles in

IEEE publications do not typically use the word “equation,”

but rather just enclose the equation number in parentheses,

e.g.,

... as can be seen in (\ref{eqn_example}).

IEEE’s two column format puts serious constraints on how

wide an equation can be. So, a fair portion of the effort in

formatting equations usually has to be devoted to properly

breaking them. It is the author’s responsibility to ensure

that all equations fit into the given column width. In rare

circumstances, it is possible to have a few equations that span

both columns (see Section X-D1), but the vast majority of

over-length equations have to be broken across multiple lines.

IX. MULTI-LINE EQUATIONS

Perhaps the most convenient and popular way to pro-

duce multiline equations is L

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X 2ε’s eqnarray environment.

However, eqnarray has several serious shortcomings:

1) the use of 2×\arraycolsep for a column separation

space does not provide natural math spacing in the

default configuration;

2) column definitions cannot be altered;

3) it is limited to three alignment columns;

4) column alignment cannot be overridden within individ-

ual cells.

There are a number of vastly superior packages for format-

ting multiline mathematics. Perhaps the most popular is the

amsmath package [11]. Amsmath is a comprehensive work

which contains many helpful tools besides enhanced multiline

alignment environments. So, all authors should give serious

consideration to its use—regardless of what they use to gen-

erate aligned equations. One thing to be aware of is that, upon

loading, amsmath will configure L

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X to disallow page breaks

within multiline equations (even within non-amsmath defined

environments). The philosophy here is that author should

manually insert breaks where desired so as to ensure that

breaks occur only at acceptable points. To restore IEEEtran’s

ability to automatically break within multiline equations, load

amsmath like:

\usepackage{amsmath}

\interdisplaylinepenalty=2500

Another extremely powerful set of alignment tools, one

of which is a totally rewritten eqnarray environment, is

provided by mathenv.sty which is part of Mark Wooding’s

MDW Tools [17].

Finally, IEEEtran provides a fully integrated custom IEEEe-

qnarray family of commands (see Appendix F) that are de-

signed to have almost universal applicability for many different

types of alignment situations.

Nevertheless, it is instructive to show a simple example

using the standard eqnarray in order to explain some of

the fine points of math spacing under L

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X. As shown in

Table I, T

E

X normally draws from four different spacings when

typesetting mathematics. In order to produce precise (and

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TABLE I

MATH SPACINGS USED BY L

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TEX

Size Width Cmd. Used for Example

small 1/6em \, symbols a b

medium 2/9em \: binary operators a+b

large 5/18 em \; relational operators a=b

negative small −1/6em \! misc. uses ab

correct) mathematical alignments, it is crucial to understand

how to control such spacing. Consider a multiline equation

Z=x1+x2+x3+x4+x5+x6

+a+b(1)

+a+b(2)

+a+b(3)

+a+b(4)

(in typical IEEE style) which was produced by

\setlength{\arraycolsep}{0.0em}

\begin{eqnarray}

Z&{}={}&x_1 + x_2 + x_3 + x_4 + x_5 + x_6\nonumber\\

&&+a + b\\

&&+{}a + b\\

&&{}+a + b\\

&&{+}\:a + b

\end{eqnarray}

\setlength{\arraycolsep}{5pt}

Lines one through four show some possible ways the +a+b

line could be implemented.5Only number four is the correct

way for most IEEE purposes. In T

E

X’s math mode, spacing

around operators can be inhibited by enclosing them within

braces (e.g., {=}) or forced by surrounding them with “empty

ords” (e.g., {}={}). It is important to understand that the

empty ords do not have width themselves. However, their

presence causes T

E

X to place space around the operators as if

they were “next to something.” With this in mind, the first step

in the example is to set \arraycolsep to zero to prevent eq

narray from putting in the unwanted, artificial, inter-column

spacing. Placing empty ords around the equal sign then forces

the correct natural spacing. Alternatively, \arraycolsep

could have been set to 0.14 em and the empty ords around the

equal sign eliminated.6It is important to remember to restore

\arraycolsep to its default value of 5 pt after the eqnarr

ay is complete as other environments (such as array) depend

on it. (Alternatively, the structure could have been enclosed in

a group of braces to keep the change local—which has the

added advantage of not requiring that the user remember what

the correct default value is.)

The first line is incorrect because ais being indicated as

a positive quantity rather than something that must be added

to the previous line. (i.e., the +is being treated as a unary,

rather than a binary, operator.) In line two, adding an empty

ord to the right side of the plus sign does nothing, except

to demonstrate that empty ords have zero width. Adding an

5In this example, the equation numbering system is (ab)used to identify

lines.

6This assumes that 1 em in the text font has the same width as 1 em in the

math font. For the standard fonts, this is indeed the case.

empty ord to the left side of the plus sign (line three) does

engage binary spacing, but causes an unwanted7right shift

of the line. Finally, manually adding a medium space to the

right side only of the plus sign in line four does the trick. The

suppression of automatic spacing around the plus sign ({+}) is

unneeded in this case, but may be required in other alignment

environments that “expand” such operators by default.

Another way around the spacing problem is to use only

two alignment columns (as is done by amsmath.sty’s \alig

n). e.g., in the previous example, “Z=” would be contained

in the first column.

A. Cases Structures

Incidentally, the numcases (or subnumcases) environ-

ments in Donald Arseneau’s cases.sty package [18] should be

used when “cases” structures in which each branch can be

referenced with a different equation (or subequation) number

are needed:

|x|=x, for x≥0(5a)

−x, for x < 0(5b)

because those built from the array or amsmath cases envi-

ronments will have a single equation number that encompasses

both branches.

Be aware that if amsmath (which will be automatically

loaded under comsoc mode if the user did not do so) is to

be used with cases.sty, the latter should be loaded after the

former or else an error “Command \subequations alr

eady defined” may occur.

X. FLOATING STRUCTURES

Authors should keep in mind when choosing an appropriate

optional placement argument for the figure/table environments

that most IEEE journals strongly favor the positioning of

floats to the top of the page and rarely, if ever, use bottom

floats. IEEE Computer Society journals also favor top floats,

but do occasionally employ bottom floats. Furthermore, IEEE

journals never place floats in the first column of the first page

and rarely (if ever) do they do so in the second column of

the first page. Middle in-text placement (“here”) is usually

not used for IEEE work with one notable exception—IEEE

Computer Society conferences.

Note that L

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X 2ε’s float routine places footnotes above

bottom floats. To change this so that footnotes appear below

the bottom floats (as the IEEE does) invoke the \fnbelowflo

at command provided by Sigitas Tolušis’ stfloats package [19]

(see Section X-D for more features of the stfloats package).

A. Figures

Figures handled in the standard L

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X manner. For example:

\begin{figure}[!t]

\centering

\includegraphics[width=2.5in]{myfigure}

\caption{Simulation results for the network.}

7The IEEE normally wants all of the lines left aligned, but there are cases

when such an indention may be desirable.

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\label{fig_sim}

\end{figure}

Note that (1) figures should be centered via the L

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X\cent

ering command—this is a better approach than using the ce

nter environment which adds unwanted vertical spacing; (2)

the caption follows the graphic; and (3) any labels must be

declared after (or within) the caption command.

When referring to figures in typical IEEE papers, authors

should use the abbreviation “Fig.”, but in IEEE Computer

Society conference papers they should use the full word

“Figure”. IEEEtran provides the string macro \figurename

which contains the correct name to use for the given formatting

mode.

The \includegraphics command is the modern, pre-

ferred, way of including images and provides a flexible in-

terface that makes it easy to scale graphics to size. To use it,

the graphics or graphicx (the latter is recommended) must first

be loaded.

It is strongly recommended that authors be familiar with the

graphics package documentation [20] as well as Keith Reck-

dahl’s excellent Using Imported Graphics in L

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X 2ε[21]. The

reader is reminded that the “draftcls” or “draftclsnofoot”, not

“draft”, class option must be selected in order to get draft

papers with visible figures.

As explained in Appendix D, Encapsulated PostScript (EPS)

or Portable Document Format (PDF) is the preferred graph-

ics format for L

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X work. Furthermore, the user’s draw-

ing/graphing application should be capable of outputing di-

rectly in EPS (or PDF) vector form (which will not degrade

or pixelize when magnified)—although photos will likely have

to be in (EPS/PDF/JPEG/PNG) bitmap form. Be aware that the

use of pdfL

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X is required for image formats other than EPS.

The psfrag package [22] might also be of interest. Psfrag

allows the user to “go into” an EPS graphic and replace text

strings contained in it with real L

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E

X code. In this manner,

L

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E

X’s extensive support of mathematical symbols and fonts

can be extended to figures made with applications with more

modest glyph support. Using psfrag does require the use of the

dvips DVI to PostScript conversion step (not pdfL

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X’s PDF

mode) as some of the features of the PostScript language have

to be utilized.8pdfL

A

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X users can use psfrag by “preprocess-

ing” their figures by importing them into a dummy document

using psfrag, running L

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X followed by dvips, then converting

the PostScript output to a PDF graphic for direct importation

into the main document which is then processed by pdfL

A

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X.

There is additional usage information on psfrag in the Using

Imported Graphics in L

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X 2εguide [21].

1) Subfigures: Subfigures can be obtain via the use of

Steven Douglas Cochran’s subfigure [23] or subfig [24] pack-

ages. Be forewarned that the former is no longer being

maintained and, although self-contained and compatible with

IEEEtran, is becoming incompatible with an increasing num-

ber of other L

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X packages including fixltx2e.sty. For this

reason, subfigure.sty is not recommended for new work and

will not be covered here.

8PDF is much like a subset of PostScript—the latter is a Turing complete

programming language, the former is not.

It is important to note that subfig.sty package options are

usually required to obtain IEEE compliant subfigure captions.

Furthermore, compsoc format requires a larger sans serif font

than the serif footnote size font used in traditional IEEE for-

matting. There is a further complication with subfig.sty in that

this package depends on caption.sty, which, in its default con-

figuration, will overrride IEEEtran’s handling of captions—

resulting in non-IEEE style main captions. To prevent this,

be sure to invoke subfig.sty’s caption=false option, which

has been available since version 1.3 (2005/06/28). Thus, the

recommended way to load subfig.sty is:

\ifCLASSOPTIONcompsoc

\usepackage[caption=false,font=normalsize,labelfon

t=sf,textfont=sf]{subfig}

\else

\usepackage[caption=false,font=footnotesize]{subfi

g}

\fi

Because multiple subfigures usually require more width than

is available in a single column, they are often used within the

double column figure environment (Section X-D):

\begin{figure*}[!t]

\centering

\subfloat[Case I]{\includegraphics[width=2.5in]{subf

igcase1}

\label{fig_first_case}}

\hfil

\subfloat[Case II]{\includegraphics[width=2.5in]{sub

figcase2}

\label{fig_second_case}}

\caption{Simulation results for the network.}

\label{fig_sim}

\end{figure*}

Note how captions can be tagged to each of the subfigures as

well as to the overall figure via an optional argument to the \s

ubfloat command. However, most IEEE authors/journals do

not employ subfigure captions, but instead reference/describe

all of the subfigures (a), (b), etc., within the main caption. Be

aware that for subfig.sty to generate the (a), (b), etc., subfigure

labels the optional argument to \subfloat must be present.

If a subcaption is not desired, just leave its contents blank

(e.g., \subfloat[]). \hfil is used as a subfigure separator

to achieve equal spacing around the graphics. More complex

implementations are possible. Note that the total width of all

the subfigures on a line must be less than the text width or else

an unwanted line break will occur. Multiple lines of subfigures

can be used within a figure if needed. See the subfig.sty

documentation as well as the Using Imported Graphics in

L

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X 2εguide [21] for more details.

Axel Sommerfeldt’s modern and actively maintained sub-

caption.sty package [25] can not be recommended at this time

because it does not provide an option to prevent the underlying

caption.sty from taking control of main caption formatting

away from IEEEtran.

B. Algorithms

IEEE publications use the figure environment to contain

algorithms that are not to be a part of the main text flow.

Peter Williams’ and Rogerio Brito’s algorithmic.sty package

[26] or Szász János’ algorithmicx.sty package [27] (the latter is

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TABLE II

A SIMPLE EXAMPLE TABLE

First Next

1.0 2.0

designed to be more customizable than the former) may be of

help in producing algorithm-like structures (although authors

are of course free to use whatever L

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X commands they are

most comfortable with in this regard). However, do not use

the floating algorithm environment of algorithm.sty (also by

Williams and Brito) or algorithm2e.sty (by Christophe Fiorio)

as the only floating structures IEEE uses are figures and tables.

Furthermore, IEEEtran will not be in control of the (non-IEEE)

caption style produced by the algorithm.sty or algorithm2e.sty

float environments.

C. Tables

Tables are handled in a similar fashion, but with a few

notable differences. For example, the code

\begin{table}[!t]

\renewcommand{\arraystretch}{1.3}

\caption{A Simple Example Table}

\label{table_example}

\centering

\begin{tabular}{c||c}

\hline

\bfseries First & \bfseries Next\\

\hline\hline

1.0 & 2.0\\

\hline

\end{tabular}

\end{table}

results in Table II. Note that the IEEE places table captions

before the tables and, given that they serve much like titles,

are usually capitalized except for words such as a, an, and, as,

at, but, by, for, in, nor, of, on, or, the, to and up, which are

usually not capitalized unless they are the first or last word of

the caption.

Be aware that, to prevent a change of meaning that would

result from case changes, the IEEE generally uses the standard

text font, not the small caps font, when rendering units as well

as letters in math in table captions. This can be achieved via

the use of \upshape:

\caption{Diagnosis of Rotor Faults in a DRFOC Drive U

sing the VCT(Flux Loop Bandwidth (FLB) = 10 {\upshap

e Hz}; 75% Load; 1450 {\upshape r/min})}

Thanks to Zhaowen Hou for providing information on this

topic as well as the above example.

Within the table environment, the default text size is foot-

notesize which is what IEEE typically uses for tables. When

using the tabular environment to construct tables, it is usually

a good idea to increase the value of \arraystretch above

unity to “open up” the table rows a tad. Also, IEEE often

uses tables with “open sides,” (without vertical lines along

each side) although the “closed side” form (e.g., Table I) is

more commonly used for the tables within this document.

Unfortunately, the standard L

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has a number of shortcomings. Two notable problems are (1)

TABLE III

THE SKEWING ANGLES (β)FOR Mu(H) + X2

AND Mu(H) + HX a

H(Mu) + F2H(Mu) + Cl2

β(H) 80.9◦b83.2◦

β(Mu) 86.7◦87.7◦

afor the abstraction reaction, Mu + HX →

MuH + X.

b1 degree =π/180 radians.

the corners where lines meet are improperly formed; and (2) it

is not very flexible in terms of user control. For these reasons,

authors are urged to look into some of the other packages

for making tables. A good one that provides revised “drop-in

replacements” for both the tabular and array environments is

Frank Mittelbach’s and David Carlisle’s array package [28].

Even more powerful (and complex) is the tabular and array

environments provided by the mdwtab.sty package which is

part of Mark Wooding’s MDW Tools [17].

As an alternative, IEEEtran offers the IEEEeqnarraybox

command which can also be used to produce tables9of high

quality. See Appendix F for more details.

1) Footnotes Within Tables: Footnotes normally cannot be

placed directly within some commands and environments such

as \parbox,tabular, etc., because they become “trapped”

inside. One way around this is to split the place the footnote

marker (\footnotemark) is located (within the table) from

where the footnote text itself is declared (outside of the table

using \footnotetext).

Another approach is to use the footnote.sty package (which

is part of Mark Wooding’s MDW Tools [17]) which allows

environments to be configured so as not to trap footnotes:

\usepackage{footnote}

\makesavenoteenv{tabular}

Note that is probably not a good idea to use footnotes in

floating structures (like table) because the position of each

can move relative to one another. To put the footnote at the

end of a table instead of at the bottom of the page, just

enclose tabular, etc., inside a minipage (no footnote package

needed). A very good approach for handling footnotes within

tables (including those that float) is to use Donald Arseneau’s

threeparttable package [29] which was used to generate Table

III (the code of which is an example in the threeparttable.sty

file).

D. Double Column Floats

L

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X’s figure*and table*environments produce fig-

ures and tables that span both columns. This capability is

sometimes needed for structures that are too wide for a single

column.

It is a limitation of the L

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X 2εkernel that double column

floats cannot be placed at the bottom of pages. That is to

say “\begin{figure*}[!b]” will not normally work as

intended. Authors that need this capability should obtain and

load Sigitas Tolušis’ stfloats package [19] which patches the

9Table I was made using this command.

12 JOURNAL OF L

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L

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X 2εoutput routine to allow it to handle double column

floats at the bottom of pages. Please note that stfloats is a

very invasive package which may not work with versions of

L

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X other than the standard L

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X 2εrelease and may cause

problems with other packages that modify the output and/or

float routines (such as those that balance columns, alter the

placement of floating figures, etc.). IEEE authors are warned

not to use packages that allow material to be placed across the

middle of the two text columns (such as cuted.sty, midfloat.sty,

etc.) as the IEEE does not do this.

Another L

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X 2εlimitation (patched with stfloats or not) is

that double column floats will not appear on the same page

where they are defined. So, the user will have to define such

things prior to the page on which they are to (possibly) appear.

L

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X 2ε(patched with stfloats or not) does not attempt

to keep double and single column floats in sequence with

each other. This can be fixed by loading Frank Mittelbach,

David Carlisle and Chris Rowley’s fixltx2e package (already

installed on most L

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X systems) [30]. Note that fixltx2e.sty

is the replacement (and superset) of the older fix2col.sty [30].

However, fixltx2e/fix2col should not be used with the stfloats

package as they both modify some of the same float routines

in different ways.

Be aware that L

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X 2εkernels dated 2015 and later have

fixltx2e.sty’s corrections already built into the system in which

case a warning will be issued if an attempt is made to load

fixltx2e.sty as it is no longer needed.

Morten Høgholm’s dblfloatfix package [31] provides the

combined functionality of both the fixltx2e and stfloats pack-

ages and is now the recommended way to obtain these features.

Finally, authors should also be aware that the L

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nel (patched with stfloats or not) has a long standing limitation

in that it will not allow rubber space that spans both columns

to stretch or shrink as needed for each of the two main text

columns. Therefore, it is possible for double column floats to

cause underfull vbox errors because the remaining text height

may not be equal to an integer number of normal size lines.

The problem can occur in main text columns (on pages with

double column floats) that do not have vertical rubber spacing

(such as that around section headings, equations, etc.) and

results in underfull vbox warnings coupled with paragraphs

that are “pulled apart” from each other. To correct this, users

can manually tweak the amount of space between the double

column structure and main text by inserting a command like

\vspace*{-3pt}

(adjusted as needed) within the double column structure. Inci-

dentally, IEEEtran automatically compensates for this problem

when forming the paper title.

1) Double Column Equations: It is possible, but not pleas-

ant, to use figure*to obtain double column equations. The

IEEE rarely uses double column equations because they can

waste space, so this capability is easy to abuse. Authors

who are considering the use of a double column equation

should verify that there are a few examples of such in papers

previously published in the journal they plan to submit to.

There are complications. Although the IEEE does not place

constraints on the order of the double column equations

relative to the equations of the main text (that is to say a

set of double column equations can be at the top or bottom

of a page in which they would normally appear in the middle

had they been regular equations), the double column equation

numbers must increase as one progresses down the page (i.e.,

double column equations at the bottom of a page must be

of higher number than those at the top). Furthermore, double

column equations should appear on the same page where they

are referenced (on the page they would have appeared had

they been regular equations). Compounding the difficulty even

further is the fact that L

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X 2εwill not place double column

equations on the same page on which they are defined. Finally,

the IEEE does not generally allow other figures or tables to

come between the double column equations and the main text

(which are separated from each other by a rule). All of this

means that the place where a double column equation must be

defined has to be “disconnected” from the place where it will

eventually be referred to in the text—and the user will have

to manually intervene in the equation numbering system.

Therefore, users have to (1) define double column equations

on the page prior to the one that they are to appear; (2) reset

the equation counter when the double column equations are

defined so as not to disturb the regular equation numbers;

(3) manually set the double column equation numbers and (4)

increment the equation counter at the point the double column

equations are referenced in the text so that they are accounted

for in the numbering of the regular equations after that point.

To do all of this, it is convenient to have a “scratch pad”

counter to temporarily save equation numbers. This can be

done via a command such as

\newcounter{MYtempeqncnt}

in the preamble of the document. Now, the double column

equations are defined on the page prior to the one in which

they are to appear (and in this example supposed that they are

to be equation numbers six and seven):

\begin{figure*}[!t]

% ensure that we have normalsize text

\normalsize

% Store the current equation number.

\setcounter{MYtempeqncnt}{\value{equation}}

% Set the equation number to one less than the one

% desired for the first equation here.

% The value here will have to changed if equations

% are added or removed prior to the place these

% equations are referenced in the main text.

\setcounter{equation}{5}

\begin{equation}

\label{eqn_dbl_x}

x=5+7+9+11+13+15+17+19+21+23+25

+27+29+31

\end{equation}

\begin{equation}

\label{eqn_dbl_y}

y=4+6+8+10+12+14+16+18+20+22+24

+26+28+30

\end{equation}

% Restore the current equation number.

\setcounter{equation}{\value{MYtempeqncnt}}

% The IEEE uses as a separator

\hrulefill

% The spacer can be tweaked to stop underfull vboxes.

\vspace*{4pt}

\end{figure*}

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x=5+7+9+11+13+15+17+19+21+23+25+27+29+31 (6)

y=4+6+8+10+12+14+16+18+20+22+24+26+28+30 (7)

The result of which is shown at the top of this page. This

technique allows the definition of the equations to be posi-

tioned arbitrarily as needed so that the (floating) equations

will appear where desired. The “[!t]” option forces L

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X to

do its best to place the equations at the top of the next page.

Had it been “[!b]” instead, then the stfloats (or even better,

dblfloatfix) package would need to be loaded and the \vspac

ecommand, followed by the \hrulefill command, would

have to occur before the equations in the figure.

The double column equations can then been referenced in

the main text like:

% The previous equation was number five.

% Account for the double column equations here.

\addtocounter{equation}{2}

As can be seen in (\ref{eqn_dbl_x}) and

(\ref{eqn_dbl_y}) at the top of the page ...

Thankfully, double column equations are rare.

XI. LISTS

The traditional L

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X itemize, enumerate and description

(IED) list environments are ill-suited for producing the style

of lists used in IEEE publications. The main problem is that

they do not provide the user a means for controlling the

parameters of the resultant list. Furthermore, making global

changes to the parameters of the underlying \list will result

(often unexpectedly to a user) in the improper behavior of

other commands that depend on it, such as \quote. Finally,

L

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X’s \list considers the left margin of the list text to be

the reference point that determines how the list is positioned

relative to the left margin of the main text:

\labelwidth

z }| {

Label

\labelsep

z }| {

| {z }

\leftmargin

List Text

This contrasts with IEEE lists which use the label box as

the reference point for the list structure. i.e., for a given

circumstance, the list labels will be indented by a certain

amount, the list text block will be indented from the label

boxes by a given amount and these spacings will determine

the position of the list text.

For these reasons, IEEEtran provides enhanced IED list

environments that make it much easier to produce IEEE style

lists. The underlying \list remains the same as in traditional

L

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E

X so as not to break code that depends upon it. IEEEtran

uses a new length variable, \IEEElabelindent, so that users

can specify IED list structures directly in IEEE fashion:

| {z }

\IEEElabelindent

\labelwidth

z }| {

Label

\labelsep

z }| {List Text

The IEEEtran IED lists ignore all “external” changes to the list

length parameters. Instead, IED lists are controlled exclusively

via two interfaces:

1) “global” control via the \IEEEiedlistdecl command;

and

2) “local” control via an optional argument that can be

provided to \itemize,\enumerate, and \descrip

tion.

For example, declaring

\renewcommand{\IEEEiedlistdecl}{\settowidth{\labelwi

dth}{Hello}}

in an IEEEtran document will set the default width of the

label boxes in all later IED lists to be equal to the width

of “Hello”. Note: Because setting a \labelwidth is so

commonly performed, IEEEtran provides a command: \IEEE

setlabelwidth{X} which is a shorter form of: \settowid

th{\labelwidth}{X}.

The local control is used if the parameters are to apply only

to an individual IED list:

\begin{itemize}[\IEEEsetlabelwidth{$\gamma$}]

Within an IED list, the local control is executed just after the

global control and therefore, the commands in the local control

can both augment and countermand those in the global control.

Please note that the code in the local and global controls are

executed in the same manner as normal L

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X code. Therefore,

the user should ensure that unwanted blank spaces do not

appear in the controls. If a control definition is too long to

fit on one line, shield the end of lines with “%” to prevent

them from being interpreted as blanks (Section IV-B1 has

some information on this topic). Also, note that the L

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X

parser requires that braces be placed around commands with

optional arguments that are placed directly within the optional

arguments of other commands:

\begin{itemize}[{\mycmd[1]{example}}]

This IEEEtran IED implementation makes it easy to control

IED lists, even when they are deeply nested.

The default spacings the IED lists use are stored in various

length (not macro) commands. Changes to these “master”

defaults are rarely needed and should be done only at the

beginning of the document, not in the IED list controls. These

constants will now be briefly explained.

\IEEEilabelindent: This length is the default amount

the itemized list label boxes are indented from the left mar-

gin. The IEEE seems to use at least two different values.

For example, in the IEEE/OSA JOURNAL OF LIGHTWAVE

TECHNOLOGY and the IEEE JOURNAL ON SELECTED AR-

EAS IN COMMUNICATIONS, they tend to use an indention

equal to \parindent, while for IEEE TRANSACTIONS ON

COMMUNICATIONS they tend to indent itemized lists a little

more (1.3\parindent). The shorter length is stored as \IE

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EEilabelindentA and the longer as \IEEEilabelindent

B. The default is to use the shorter version. To use the longer

version do a

\setlength{\IEEEilabelindent}{\IEEEilabelindentB}

at the beginning of the document.

\IEEEelabelindent: This length is the default amount

the enumerated list label boxes are indented from the left

margin. Normally, the same as \parindent.

\IEEEdlabelindent: Ditto for description list labels. Nor-

mally, the same as \parindent.

\IEEEiednormlabelsep: This length is the normal de-

fault spacing between the IED list label boxes and the list

text.

\IEEEiedmathlabelsep: For nomenclature description

lists (a list of math symbols and their explanations), the IEEE

usually increases the separation between the terms and the

definitions. This length is set to the longer than normal length.

To invoke its use, just issue the command \IEEEusemathla

belsep in a list control.

\IEEEiedtopsep: This length is the extra vertical sepa-

ration put above and below each IED list. The IEEE usually

puts a little extra spacing around each list. However, this extra

spacing is barely noticeable.

\IEEElabelindentfactori through \IEEElabelin

dentfactorvi: These contain the factors by which the

effective \IEEElabelindent is reduced as the list nesting

depth increases. The IEEE normally decreases the amount of

indention as the list nesting level increases because there isn’t

much room to indent with two column text. IEEEtran has

an “automatic indention cut-back” feature that provides this

behavior. The actual amount the label boxes will be indented

is \IEEElabelindent multiplied by the \IEEElabelinden

tfactorX corresponding to the level of nesting depth (where

“X” is the nesting depth in roman numerals). This provides a

means by which the user can alter the effective \IEEElabel

indent for deeper levels. There may not be such a thing as

correct “standard IEEE” values. What the IEEE actually does

may depend on the specific circumstances. The first list level

almost always has full indention. The second levels usually

have only 75% of the normal indentation. Third level and

greater nestings are very rare, and probably don’t use any

indentation. These factors are not lengths, but rather constant

macros like \baselinestretch so \renewcommand should

be used if they need to be changed. The default values are

\IEEElabelindentfactori 1.0

\IEEElabelindentfactorii 0.75

\IEEElabelindentfactoriii 0.0

\IEEElabelindentfactoriv 0.0

\IEEElabelindentfactorv 0.0

\IEEElabelindentfactorvi 0.0

The use of these factors in IED lists may be suspended by

issuing the command \IEEEnolabelindentfactortrue in

a list control (which has the same effect as setting all the

indent factors to 1.0).

Normally, IEEEtran automatically calculates \leftmargin

based upon the current values of \IEEElabelindent,\labe

lwidth and \labelsep. To stop this auto-calculation so that

a manually specified value of \leftmargin is used instead,

just use \IEEEnocalcleftmargintrue in a list control. This

feature should not be needed during the course of normal IEEE

related work.

IEEEtran provides a means to manually specify the justifica-

tion within the IED list label boxes. The commands \IEEEied

labeljustifyl,\IEEEiedlabeljustifyc and \IEEEied

labeljustifyr can be used in a list control to justify the list

labels to the left, center, and right sides, respectively. Itemize

and enumerate lists automatically default to right justification,

while description defaults to left justification. The justification

commands should not be needed during the course of normal

IEEE related work.

In addition to modifying the behavior of itemize,enumer

ate and description, IEEEtran also provides the respective

aliases IEEEitemize,IEEEenumerate and IEEEdescript

ion, which provides a way for the user to access the IEEE

style list environments even in the event another package is

loaded that overrides the IED list environments. For special-

ized applications, the original L

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retained as LaTeXitemize,LaTeXenumerate and LaTeXde

scription.

A. Itemize

The itemized lists will normally automatically calculate the

width of whatever symbol the current list level is using so that

a user can just call \begin{itemize}...\end{itemize}

without doing anything special. Furthermore, the auto-label-

width feature will work properly even if \labelitemX has

been redefined (where “X” indicates “i,ii, .. iv”, whichever

is appropriate) before the list begins. However, if any item

symbols are to be specified via \item[X] (this is rare and may

well be nonstandard as far as IEEE related work is concerned),

then the following form can be used:

\begin{itemize}[\IEEEsetlabelwidth{Z}]

\item[X] blah

\item[Y] blah

.

.

\end{itemize}

where “Z” is the longest label in the list.

B. Enumerate

The important thing to note about enumerated lists is that

the \labelwidth will default to the length of “9)” in the

normal size and style. Therefore, the width of the longest label

will have to be manually specified if any of the following

conditions are true:

1) a top level list has more than 9 items;

2) a relevant \labelenumX or \theenumX has been rede-

fined;

3) \item[X] has been used to manually specify labels;

4) the labels are using a font that is not the normal size

and style;

5) the enumerated list is nested (i.e., not at the top level)

and is therefore not using Arabic digits as labels.

For example:

SHELL: HOW TO USE THE IEEETRAN L

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\begin{enumerate}[\IEEEsetlabelwidth{12)}]

\item blah

\item blah

.

.

% 12 items total

\end{enumerate}

C. Description

Generally speaking, the longest label width will always have

to be specified for description lists. Furthermore, the author

may wish to use \IEEEmathlabelsep for \labelsep when

building a math symbol list. For example:

\begin{description}[\IEEEsetlabelwidth{$\alpha\omega

\pi\theta\mu$}\IEEEusemathlabelsep]

\item[$\gamma\delta\beta$] Is the index of..

\item[$\alpha\omega\pi\theta\mu$] Gives the..

.

.

\end{description}

Sometimes it can be difficult to ascertain from inspection

which of the labels is the longest. For such cases, a little

diagnostic code may be helpful to measure a length and then

to display the result on the console:

\newlength{\mydiaglen} % put in preamble

.

.

\settowidth{\mydiaglen}{$\alpha\beta\gamma$}

\showthe\mydiaglen

XII. THEOREMS AND PROOFS

Theorems and related structures such as axioms, corollaries

and lemmas, are handled in the traditional L

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X fashion. The

user must first declare the structure name via the

\newtheorem{struct_type}{struct_title}[in_counter]

command where struct_type is the user chosen identifier

for the structure, struct_title is the heading that is used for

the structure and in_counter is an optional name of a counter

whose number will be displayed with the structure number

and whose update will reset the structure counter. Most IEEE

papers use sequential theorem numbering throughout the entire

work, so an in_counter is usually not specified. However,

those papers that do use in_counter usually use “section”

such that the section number is the first part of each theorem

number. After the structure is defined it can be used via

\begin{struct_type}[extra_title]

.

.

\end{struct_type}

where extra_title is an optional name that is displayed

with the structure.

For example, the most common way to do theorems would

be to use

\newtheorem{theorem}{Theorem}

followed as needed by environments like

\begin{theorem}[Einstein-Podolsky-Rosenberg]

Sometimes it is desirable that a structure share its counter

with another structure. This can be accomplished by using the

alternate form of \newtheorem

\newtheorem{struct_type}[num_like]{struct_title}

where num_like is the name of an existing structure.

IEEE theorem numbers are prefixed by the section number

they were defined in (e.g., 2.5). This presents a difficulty with

appendices (especially when numbered with Roman numerals)

because the theorem numbers will not be unique. To remedy

this, within Roman numbered appendices, IEEEtran will add

an “A” prefix (e.g., A2.5). For Alpha number appendices,

theorem numbering is more straightforward (e.g., A.5, B.5,

etc.). For a single appendix, a constant “A” prefix is used (e.g.,

A.5).

A. Proofs

Proofs are easily handled by the predefined IEEEproof

environment:

\begin{IEEEproof}

.

.

\end{IEEEproof}

The Q.E.D. symbol “ ” is automatically placed at the end of

each proof. If needed, the symbol can be manually accessed

via the \IEEEQED command. Both the closed (default) “ ”

and open “ ” forms are provided as \IEEEQEDclosed and

\IEEEQEDopen, respectively. To change the default from

closed to open (some journals and/or authors prefer the open

form), just redefine \IEEEQED as desired:

\renewcommand{\IEEEQED}{\IEEEQEDopen}

IEEEproof also supports an optional argument which allows

the default string “Proof” to be overridden:

\begin{IEEEproof}[Proof of Theorem \ref{thm:my}]

XIII. END SECTIONS

A. Appendices

The \appendix command is used to start a single appendix.

An optional argument can be used to specify a title:

\appendix[Proof of the Zonklar Equations]

After issuing \appendix, the \section command will be

disabled and any attempt to use \section will be ignored

and will cause a warning message to be generated. (The

single appendix marks the end of the enumerated sections

and the section counter is fixed at zero—one does not state

“see Appendix A” when there is only one appendix, instead

“see the Appendix” is used.) However, all lower \subsecti

on commands and the \section*form will work as normal

as these may still be needed for things like acknowledgments.

\appendices is used when there is more than one ap-

pendix section. \section is then used to declare each ap-

pendix:

\section{Proof of the First Zonklar Equation}

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The mandatory argument to section can be left blank (\sect

ion{}) if no title is desired. It is important to remember to

declare a section before any additional subsections or labels

that refer to section (or subsection, etc.) numbers. As with \a

ppendix, the \section*command and the lower \subsec

tion commands will still work as usual.

There are two appendix numbering conventions used by

IEEE. Capital letters (e.g., “Appendix B”) and Roman nu-

merals (e.g., “Appendix II”). The former appears to be more

popular and is the IEEEtran default. Use the IEEEtran class

option romanappendices to get Roman numbered appendices.

Some authors prefer to have the appendix number to be part

of equation numbers for equations that appear in an appendix.

This can be accomplished by redefining the equation numbers

as

\renewcommand{\theequation}{\thesection.\arabic{equa

tion}}

before the first appendix equation. For a single appendix, the

constant “A” should be used in place of \thesection.

B. Acknowledgments

Acknowledgments and other unnumbered sections are cre-

ated using the \section*command:

\section*{Acknowledgment}

\addcontentsline{toc}{section}{Acknowledgment}

The second, optional, command is needed to manually add

such sections to the table of contents (which is rarely used,

but some authors may do so with draft papers) as well as the

document’s PDF bookmarks (if using hyperref.sty).

Note that IEEE Computer Society papers typically use the

plural form “Acknowledgments”.

C. Bibliographies

Bibliographies are most easily (and correctly) generated

using the IEEEtran BIBT

E

X package [32] which is easily

invoked via

\bibliographystyle{IEEEtran}

\bibliography{IEEEabrv,mybibfile}

See the IEEEtran BIBT

E

X package documentation for more

information.

When submitting the document source (.tex) file to external

parties, it is strongly recommended that the BIBT

E

X .bbl file

be manually copied into the document (within the traditional

L

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X bibliography environment) so as not to depend on

external files to generate the bibliography and to prevent the

possibility of changes occurring therein.

D. Biographies

Biographies for journal articles are created using the IEEE-

biography environment which supports an optional argument

for the inclusion of a photo:

\begin{IEEEbiography}[{\includegraphics[width=1in,he

ight=1.25in,clip,keepaspectratio]{./shell}}]{Michael

Shell}

.

.

\end{IEEEbiography}

Note the extra set of braces that are required to prevent the

L

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E

X parser from becoming confused when commands with

optional arguments are used within an optional argument of

another command. Alternatively, a L

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E

X macro (command)

could be defined to facilitate a shorthand notation for the

author photos. If the optional argument is not used, space will

be reserved for a photo and the message “PLACE PHOTO

HERE” will be displayed in place of a photo.

IEEEtran is a tad overly cautious about preventing the

IEEEbiography photo area from being broken across pages.

If it looks as though a IEEEbiography should be able to be

“squeezed” at the end of a page, but instead it begins on a

new page, try inserting

\vspace*{-2\baselineskip}

or so before the IEEEbiography and see if it can fit.

IEEE’s algorithm for spacing around biographies can be a

tad complex because esthetics must be considered. IEEEtran

places \vfil above biographies. This allows the user to shove

biographies down or up as desired by placing the infinitely

more stretchable \vfill before or after the biographies.

The photo area is 1 in wide and 1.25 in long. The IEEE

recommends that author photo images should be of 220 dpi

(dots per inch) resolution and in gray scale with 8 bits/sample.

If no photo is available, the \IEEEbiographynophoto

environment, which does not support an optional argument

or reserve space for a photo, can be used instead.

XIV. LAST PAGE COLUMN EQUALIZATION

The IEEE (coarsely) equalizes the lengths of the columns

on the last page. The balance is coarse in the sense that

reference or IEEEbiography entries are not usually broken—so

the column lengths are not usually perfectly equal.

Balancing the last two columns is especially important for

camera ready work. It is recommended that authors use the

manual approach by putting in \newpage at the appropriate

point or \enlargethispage{-X.Yin} somewhere at the top

of the first column of the last page where “X.Yin” is the

amount to effectively shorten the text height of the given page.

Sometimes such a command has to be located between

bibliography entries. This can be a problem because, although

the command can be placed within the .bbl file, it will get

overwritten the next time BIBT

E

X is run. For this situation,

IEEEtran offers a way to invoke commands just before a given

reference number via the \IEEEtriggeratref{} command.

For instance, issuing the command

\IEEEtriggeratref{10}

before the bibliography will insert a page break just before

reference number ten. The command that is executed defaults

to \newpage. However, this can be changed via the \IEEE

triggercmd command:

\IEEEtriggercmd{\enlargethispage{-5.35in}}

Note that manually set break points or page sizes will have to

be readjusted if the document content ever changes.

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X CLASS 17

There are L

A

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E

X packages, such as balance.sty [33] and

flushend.sty [34], that are designed to automatically balance

the columns on the last page. Flushend does not require the

placement of any special command in the first column of the

last page, balance.sty may. However, the use of these packages

is not recommended because they are known to be less than

perfectly reliable in their operation. The author of balance.sty

does not guarantee that it will work with every possible type

of page, especially pages with figures. Under certain circum-

stances, flushend.sty will cause a spacing anomaly between

two lines within a reference in the second column of the last

page (becomes larger than the space between references). This

problem seems to result because the bibliography in IEEEtran

is a list with zero space between the list items which are in

footnotesize. The problem can also occur under article.cls for

the same type of list. It may be possible to manually correct

the flushend anomaly by tweaking the spacer at the column

break via a flushend command such as “\atColsBreak{\vs

kip-2pt}”, but having to do so partially defeats the purpose

of using the package in the first place. If using flushend.sty or

balance.sty, be sure to check the document carefully for any

spacing problems—especially on the last page.

APPENDIX A

INSTALLING IEEETRAN

First of all, users should be aware that, depending on the

target operating system of the IEEEtran archive packaging

(e.g., .tar.gz for Unix, or .zip for MS Windows), the plain text

based IEEEtran files (.bst, .cls, .sty, .tex, etc.) may use one of

two different types of end-of-line character conventions. Unix

(including Mac OS X) systems use line feed <lf> (0x0A),

while MS Windows systems use carriage return/line feed pairs

<cr><lf> (0x0D 0x0A) to signal the end of lines.10 Most

modern L

A

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E

X systems are tolerant of differing end-of-line

conventions, but some text editors aren’t. (Symptoms here

include text appearing all on one long line, double spacing,

etc.)

L

A

T

E

X .cls files can be accessed system-wide when they are

placed in the <texmf>/tex/latex directory, where <tex

mf> is the root directory of the user’s T

E

X installation. On

systems that have a local texmf tree (<texmflocal>), which

may be named “texmf-local” or “localtexmf”, it may be

advisable to install packages in <texmflocal>, rather than

<texmf> as the contents of the former, unlike that of the

latter, are preserved after the L

A

T

E

X system is reinstalled and/or

upgraded.

It is recommended that the user create a subdirectory <t

exmf or texmflocal>/tex/latex/IEEE for all IEEE

related L

A

T

E

X class and package files. On some L

A

T

E

X systems,

the directory look-up tables will need to be refreshed after

making additions or deletions to the system files. For T

E

X

Live systems this is accomplished via executing

texhash

as root. MiKT

E

X users can run

10The fact that different conventions exist for plain text is, of course, an

absurdity in itself. See the Wikipedia article “Newline” at http://en.wikipedia.

org/wiki/Newline for the history and details.

initexmf -u

to accomplish the same thing.

Users not willing or able to install the files system-wide can

install them in their personal directories, but will then have to

provide the path (full or relative) in addition to the filename

when referring to them in L

A

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X.

APPENDIX B

POSTSCRIPT/PDF OUTPUT

Some L

A

T

E

X systems are not properly configured to produce

quality PostScript and/or PDF output. This has historically

been more of a problem with IEEE-related work because the

unique font combination the IEEE uses has been known to

trigger problems with some L

A

T

E

X setups. Fortunately, these

types of problems are now relatively uncommon on modern

L

A

T

E

X systems.

To assist IEEE authors in detecting and correcting prob-

lems with L

A

T

E

X PostScript/PDF generation, the “Testflow”

diagnostic suite was developed [35]. Authors are encouraged

to take the time to go through the testflow diagnostic and

identify and correct potential problems before their L

A

T

E

X

systems have to be relied on for production work. Papers with

problems such as incorrect margins, font types, PDF format

errors and/or improper font embedding can incur delays during

the manuscript acceptance process.

APPENDIX C

OTHER USEFUL OR RELATED EXTERNAL PACKAGES

A. The acronym.sty Package

Tobias Oetiker’s acronym.sty [36] may be useful with

papers that have a lot of acronyms. However, beware of a

compatibility issue between the acronym environment and the

IEEEtran description lists (see Appendix E).

B. The url.sty Package

Papers that contain URLs, email address, etc., can likely

benefit from the use of Donald Arseneau’s url.sty L

A

T

E

X

package [37] which provides for more intelligent line breaking

within such structures. Note that IEEEtran.cls automatically

sets the url font style of url.sty to “same” (that is, URLs will

be rendered in the same font as the text they appear in) as

IEEE journals do. To override this, the author must place the

\urlstyle after \begin{document}.

C. The IEEEtrantools Package

Some of the unique commands provided by the IEEEtran

L

A

T

E

X class may be of use in non-IEEE related work using

other class files (e.g., dissertations, technical reports, etc.).

The IEEEtrantools.sty package [38] provides several popular

IEEEtran commands including \IEEEPARstart, the IEEE

style IED list environments, the IEEEeqnarray family of

commands, the IEEEproof environment and \IEEEauthor

refmark. The IEEEtrantools package is not needed under,

and should not be loaded with, the IEEEtran class. See the

IEEEtrantools documentation for more details.

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APPENDIX D

COMMON USER MISTAKES

Many user mistakes with IEEEtran involve doing too much

rather than too little. Older class files may have required hacks

in order to get the formatting closer to that of the IEEE. These

tweaks are no longer needed. Users should carefully check

all the loaded packages to ensure that they are still useful

under the latest version of IEEEtran. Don’t load packages just

because “this is the way it always has been done.” The same

is true for manually adjusted spacing, margins, paper sizes,

etc.

Below are a few of the more commonly encountered mis-

takes to avoid.

Placing labels before captions: This is considered to be

one of the most frequent mistakes made in L

A

T

E

X of all time.

Remember that \label must be placed after or within \cap

tion to be able to reference figures/tables properly. As it is

\caption that actually sets up the reference counter, \labe

l’s placed prior to \caption will refer to the section number,

instead of the desired figure/table number.

Altering the default fonts: Authors should allow IEEEtran

to manage the fonts. Unless specifically instructed otherwise,

such as under comsoc mode or in the author instructions of the

specific conference/journal being submitted to, do not attempt

to use packages that override the default fonts such as pslatex,

mathptm, etc.

Altering the default spacings, section heading styles,

margins or column style: Authors should not attempt to

manually alter the margins, paper size (except as provided

in IEEEtran class options) or use packages that do so (geom-

etry.sty, etc.). There should be no need to add spacing around

figures, equations, etc., (except possibly for double column

floats as described in Section X-D).

Using bitmapped graphics for line art: L

A

T

E

X has always

favored the use of Encapsulated PostScript (EPS) or under

pdfL

A

T

E

X, Portable Document Format (PDF), (which can be

considered to be a type of subset of PostScript), for graphics

(see Section X-A for more information), and for good reason.

EPS/PDF supports both vector (that is, containing objects

such as lines, circles, etc., that are mathematically described)

and bitmap (that is, containing only samples in the form

of pixels) images. The former should always be used for

drawings, graphs, charts, etc., while the latter usually has

to be employed with photos (because their contents usually

cannot be easily described mathematically). The drawing and

graphing tools used by the author should be capable of

outputting directly11 in vector (EPS or PDF) format. Vector

EPS/PDF images can be scaled, rotated and magnified without

undergoing degradation such as pixelization or becoming gray

or “jaggedy.” For photos, the IEEE recommends the use of

EPS/PDF (which is easy to directly import into (pdf)L

A

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X in a

portable manner), PNG or TIFF. For author photos JPEG (JPG)

is usually acceptable. The use of other graphic formats such

as BMP, EMF, VSD, etc., is unacceptable for IEEE journals.

11Once an image in EPS/PDF vector form is converted to a bitmap form

(GIF, PNG, TIFF, JPEG, etc.) it will almost always be irretrievably locked

into bitmap form even if it is later converted back into EPS/PDF.

Some IEEE conferences may be more liberal with regard to

the types of graphics formats they accept.

Using bitmapped fonts and/or not embedding and

subsetting all document fonts: Authors should check their

system with the testflow diagnostic [35] to ensure that only

vector (Type 1) fonts are being used and that all fonts are

embedded and subsetted. A document that uses bitmapped

fonts and/or fails to contain all (and only) the needed font

glyphs may be rejected by the IEEE. Watch out for graphical

drawing applications that produce output with these problems

(suspect this if the problem goes away when the figures are

not included).

Using older graphics packages: Authors should not use

anything other than the graphics and/or graphicx (preferred)

package for figures. Older interfaces such as psfig, epsf, etc.,

have been obsolete for many years.

Failing to properly divide long equations: It is the author’s

responsibility to ensure that all equations fit within the width of

their columns. Admittedly, breaking an equation is not always

easy to do and two column formatting places serious con-

straints on allowed equation width. However, only the author

can divide his/her equation without unintentionally altering its

meaning or affecting readability. Using subfunctions is a valid

way to reduce to width of an equation, but altering the math

font size is not.

Manually formatting references: Not only is this error

prone, but requires a lot of work as well. It is better to use

the IEEEtran BIBT

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X style [32].

APPENDIX E

KNOWN ISSUES

acronym.sty: The acronym environment will have a prob-

lem with IEEEtran because of the modified IEEE style

description list environment. The optional argument of the

acronym environment cannot be used to set the width of the

longest label. A workaround is to use \IEEEiedlistdecl to

accomplish the same thing:

\renewcommand{\IEEEiedlistdecl}{\IEEEsetlabelwidth{S

ONET}}

\begin{acronym}

.

.

\end{acronym}

\renewcommand{\IEEEiedlistdecl}{\relax}% reset back

cite.sty: Versions prior to 5.0 (2009-03-20) will not hyper-

link citation numbers under hyperref.sty.

hyperref.sty: Versions prior to 6.72u will interfere with the

optional argument to \appendix.

Small caps font variations: The small caps font used in

the free L

A

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X systems have about 80% the height of normal

sized letters. However, the small caps font the IEEE uses in the

journals is slightly smaller with a ratio of around 75%. So, the

widths of the section headings produced under the free L

A

T

E

X

systems will be slightly wider than that used in actual journals.

The small caps font used in many commercial L

A

T

E

X systems

(such as those from YandY) has a ratio of about 65%. So,

those systems will produce section headings that are narrower

than those in IEEE publications. Such variations should not

be cause for concern.

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APPENDIX F

THE IEEEEQNARRAY COMMANDS

(Optional—for advanced users)

Virtually all L

A

T

E

X alignment commands such as \eqnarr

ay,\array and \tabular are based on the T

E

X command

\halign. L

A

T

E

X’s goal of simplifying the use of \halign is

noble. However, in hiding much of the lower level interface, a

fair degree of flexibility is lost. This has resulted in the devel-

opment of several packages such as amsmath [11], array.sty

[28], and the MDW tools [17], each of which provides much

more powerful alignment structures.

IEEEtran also provides its own unique set of alignment

tools which are known as the IEEEeqnarray family. The

design philosophy of the IEEEeqnarray family is to provide

a L

A

T

E

X alignment interface that is based more closely on the

underlying \halign, but to couple this with high level col-

umn definition management and automated preamble building

mechanisms (which are tedious to do in T

E

X). As a result,

the IEEEeqnarray family of commands are flexible enough

to be almost universal replacements for all the other L

A

T

E

X

commands for producing multiline equations and aligned box

structures such as matrices and tables of text and/or mathe-

matics. Because the user is shielded less from the \halign

underpinnings, the rules of operation are more involved. So,

the IEEEeqnarray commands are aimed primarily toward the

more advanced L

A

T

E

X users.

The use of the IEEEeqnarray family of tools described

in this section is totally optional. The IEEEeqnarray code

is self-contained and does not depend on other alignment

packages—which can be used along side, or in place of, it. The

IEEEtrantools.sty package (See Appendix C-C) is available

for those who wish to use the IEEEeqnarray family outside of

IEEEtran.cls.

Recommended sources of information on the use of IEEEe-

qnarray include Stefan M. Moser’s How to Typeset Equations

in L

A

T

E

X[6] and Tobias Oetiker’s The Not So Short Introduction

to L

A

T

E

X 2ε[5].

A. IEEEeqnarray

The IEEEeqnarray environment is for multiline equations

that occupy the entire column. It is used in much the same

way as \eqnarray, but with two additional arguments, one

of which is mandatory and the other is optional:

\begin{IEEEeqnarray}[decl]{cols}

.

\end{IEEEeqnarray}

The optional argument is for commands that are to be executed

within the environment, but before the alignment actually be-

gins. This is just like the local control of the IEEEtran IED list

environments. There is also a global control, \IEEEeqnarray

decl, which is executed just prior to the local control. By

default, \IEEEeqnarraydecl is defined to be \relax. As

mentioned in Section XI, users should be careful not to allow

unwanted spaces to occur in these controls because such

things will appear just before the IEEEeqnarray structure.

Furthermore, remember that, to prevent the L

A

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E

X parser from

TABLE IV

IEEEEQNARRAY PREDEFINED COLUMN TYPES

I.D. Description I.D. Description

lleft math vvertical rule

ccentered math vv two vertical rules

rright math Vdouble vertical rule

Lleft math with ords VV two double vertical rules

Ccentered math with ords hhorizontal rule

Rright math with ords Hdouble horizontal rule

sleft text xempty

tcentered text Xempty math

uright text

Note: S,T,U,p, and Pare likely to be used in future versions.

TABLE V

IEEEEQNARRAY PREDEFINED COLUMN SEPARATION (GLUE) TYPES

I.D. Width*I.D. Width

!−1/6em .0.5\arraycolsep

,1/6em /1.0\arraycolsep

:2/9em ?2.0\arraycolsep

;5/18 em *0pt plus 1fil

’1em +1000pt minus 1000pt

"2em -0pt

*All em values are referenced to the math font.

1em =\quad,2em =\qquad

becoming confused, the contents of an optional argument must

be enclosed in braces if the argument contains commands with

optional arguments.

The mandatory argument cols contains the column and

inter-column separator spacing (“inter-column tabskip glue”

in T

E

Xspeak) type specifiers. Column types are identified by

letters. Several predefined column types are available as shown

in Table IV. There are two kinds of glue types. Predefined glue

types are indicated by various punctuation marks as shown in

Table V. User defined glue types are indicated by numbers.

The rules for placing these specifiers are as follows: (1) no

two glue specifiers can appear next to each other—they are

not additive and must be separated from each other by at least

one column specifier; (2) zero inter-column spacing will be

assumed between back-to-back column specifiers; (3) because

of rule one, back-to-back numerals will be considered as being

a single glue specified by the numerical value represented by

all the digits; (4) a multiletter column specifier can be accessed

by enclosing the letters within braces (otherwise it would be

interpreted as being several single letter column specifiers).

Because of rule three, braces are not needed around multidigit

glue specifiers; (5) there must be at least one column specifier,

but there is no fixed upper limit of how many columns can be

supported; and (6) for \IEEEeqnarray, “+” centering glue

will be assumed at each end of the cols specification if

no column glue is specified there. This results in a centered

structure like \eqnarray (the 1000pt minus 1000pt glue on

each side “compresses” as needed from each side of the main

text column to center that which is between). Also, \IEEE

eqnarray automatically adds a hidden column for equation

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numbers to the right of the last specified column. Currently,

there is no support for equation numbers on the left side.12

B. Defining Column Types

New column types are defined with the

\IEEEeqnarraydefcol{col_id}{predef}{postdef}

command. The col_id argument contains the name of the

column specifier which should consist only of one or more

letters. A given column specifier, even the predefined ones, can

be redefined at will without warning or error.13 The predef

argument contains the commands that will be inserted before

each cell in the column. The postdef argument contains the

commands that will be inserted after each cell in the column.

For example,

\IEEEeqnarraydefcol{g}{\hfil$\clubsuit$}{$\diamondsu

it$\hfil}

Will define a “g” text column which will place club and

diamond suit symbols on either side of a cell’s contents and

center the respective structure within the cell. e.g.,

♣Hello♦

Using \hfil to control cell alignment allows the user

to override the column alignment on a cell-by-cell basis by

placing the infinitely more stretchable \hfill on one or both

sides of a cell’s contents. \hfill can even be placed between

items in a cell to force them apart and against the “cell walls.”

The IEEEeqnarray predefined columns are designed to allow

user overrides via \hfill whenever possible (even for the

math mode cells).

Please note that T

E

X will not allow unmatched braces within

the arguments of commands. If braces are needed, such as for

the argument of a command, they will have to be provided

within the cells themselves. For example,

\IEEEeqnarraydefcol{myp}{\parbox[c]{0.5in}}{}

\begin{IEEEeqnarraybox}{{myp}c}

{first\\second}&\alpha\\

&\beta%

\end{IEEEeqnarraybox}

defines a column type named “myp” that will place text within

a 0.5 inch wide parbox which is centered on the cell’s baseline.

Note that because the column type name consists of more than

one letter, it has to be enclosed within an extra set of braces

in the column specifications or else it would be interpreted as

three adjacent columns “m”, “y” and “p”. Also, the contents

of the cell must be enclosed within braces so that (1) the \par

box command sees the entire contents as its argument; and (2)

the newline within the parbox will not be interpreted as being

the end of the alignment row. Be aware that it can happen that

a column is given an empty cell, such as in the second row in

the example, or when entering blank separator rows. When this

happens, a \relax will appear in the column which will be

acquired as the command’s argument. Therefore, commands

in column definitions that acquire arguments from the cells

should not choke if fed \relax.

12This is not to say that its impossible with the existing capability, just

ugly.

13Thus allowing new predefined column types to be added without breaking

existing code.

For reference, the definitions of the predefined column types

are shown here:

% math

\IEEEeqnarraydefcol{l}{$\IEEEeqnarraymathstyle}{$\hfil}

\IEEEeqnarraydefcol{c}{\hfil$\IEEEeqnarraymathstyle}{$\hfil}

\IEEEeqnarraydefcol{r}{\hfil$\IEEEeqnarraymathstyle}{$}

\IEEEeqnarraydefcol{L}{$\IEEEeqnarraymathstyle{}}{{}$\hfil}

\IEEEeqnarraydefcol{C}{\hfil$\IEEEeqnarraymathstyle{}}{{}$\h

fil}

\IEEEeqnarraydefcol{R}{\hfil$\IEEEeqnarraymathstyle{}}{{}$}

% text

\IEEEeqnarraydefcol{s}{\IEEEeqnarraytextstyle}{\hfil}

\IEEEeqnarraydefcol{t}{\hfil\IEEEeqnarraytextstyle}{\hfil}

\IEEEeqnarraydefcol{u}{\hfil\IEEEeqnarraytextstyle}{}

% vertical rules

\IEEEeqnarraydefcol{v}{}{\vrule width\arrayrulewidth}

\IEEEeqnarraydefcol{vv}{\vrule width\arrayrulewidth\hfil}{\h

fil\vrule width\arrayrulewidth}

\IEEEeqnarraydefcol{V}{}{\vrule width\arrayrulewidth\hskip\d

oublerulesep\vrule width\arrayrulewidth}

\IEEEeqnarraydefcol{VV}{\vrule width\arrayrulewidth\hskip\do

ublerulesep\vrule width\arrayrulewidth\hfil}%

{\hfil\vrule width\arrayrulewidth\hskip\doublerulesep\vrule

width\arrayrulewidth}

% horizontal rules

\IEEEeqnarraydefcol{h}{}{\leaders\hrule height\arrayrulewidt

h\hfil}

\IEEEeqnarraydefcol{H}{}{\leaders\vbox{\hrule width\arrayrul

ewidth\vskip\doublerulesep\hrule width\arrayrulewidth}\hfil}

% plain

\IEEEeqnarraydefcol{x}{}{}

\IEEEeqnarraydefcol{X}{$}{$}

Note the inclusion of the commands \IEEEeqnarraymat

hstyle and \IEEEeqnarraytextstyle in the math and

text columns, respectively. These commands allow the user

to control the style of all of the math and text columns.

However, because the changes apply to all the columns, the

user will have to define new column types if different styles

are needed in the same alignment (or different styles can be

manually specified in each cell). The default definitions for

these commands are

\newcommand{\IEEEeqnarraymathstyle}{\displaystyle}

\newcommand{\IEEEeqnarraytextstyle}{\relax}

which allows the text columns to be in whatever style was in

effect when the alignment was started and the default math

style will be in display style, but can be easily changed as

needed. e.g.,

\begin{IEEEeqnarray}[\renewcommand{\IEEEeqnarraymath

style}{\scriptstyle}]{rCl}

will result in script style math columns.

The columns relating to vertical and horizontal lines will

be discussed in Appendix F-K as they are typically used only

when producing tables.

The “x” and “X” columns are basic empty text and math

mode columns without any formatting or style controls.

C. Defining Glue Types

New column separation glue types are defined with the

\IEEEeqnarraydefcolsep{colsep_id}{def}

command. The colsep_id argument contains the number of

the column separation glue specifier which should consist only

of numerals. Different glue type names must have different

numerical values. (Don’t get too cute—“007” is identical to

“7”.) User defined column glue specifiers can be redefined

at will without warning or error. The def argument contains

SHELL: HOW TO USE THE IEEETRAN L

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the width of the given glue type. Widths may be specified as

absolute values or reference length commands:

\IEEEeqnarraydefcolsep{9}{10pt}

\IEEEeqnarraydefcolsep{11}{2\tabcolsep}

The glue type widths are not evaluated when defined, but are

evaluated each time they are actually referenced as IEEEeq-

narray column specifiers. Thus, for the second definition in

the example above, if \tabcolsep were to be revised after

the glue type was defined, the revised value would be what is

used.

Rubber lengths are allowed too. The fact that the centering

glue “+” is a known value can be exploited to achieve some

interesting effects. For example,

\IEEEeqnarraydefcolsep{17}{200pt minus 200pt}

will produce a column separation glue that is always 1/5of

the width of the distance from the equation sides to the ends

of the main text columns. And, of course, “+” can be used as

needed to produce groups of equally spaced equations as in

amsmath’s \align:

\begin{IEEEeqnarray}{Rl+Rl+Rl}

D. A Simple Example of Use

The example in Section IX can be implemented using

\IEEEeqnarray via

\begin{IEEEeqnarray}{rCl}

Z&=&x_1 + x_2 + x_3 + x_4 + x_5 + x_6\IEEEnonumber\\

&&+\:a + b%

\end{IEEEeqnarray}

As shown in Table IV the “C” column type is a centered math

mode column with empty ords (“{}”) on either side. So, there

is no need to place empty ords around the equal sign. As with

\eqnarray, the &separate the column cells and are where

the inter-column separation glue will appear (when nonzero).

Note the presence of the %at the end of the second row.

T

E

X does not ignore spaces that occur before commands or

&column delimiters, but does ignore those that occur after.

Most L

A

T

E

X alignment implementations shield the user from

this behavior by removing all spacing previous to &,\\ and

\end. The IEEEeqnarray family does not do this! So, it is

important to prevent spaces (including implied ones at the end

of lines) from occurring before such commands unless they are

wanted. Suspect this problem if there is an unexplained offset

within a column. In the given example, unwanted spacing is

not an issue because end spacing is ignored in math mode

anyway. However, it would be an issue if the columns used

text mode instead.

Alternatively, one could use a two column form:

\begin{IEEEeqnarray}{Rl}

Z=&x_1 + x_2 + x_3 + x_4 + x_5 + x_6\IEEEnonumber\\

&+\:a + b%

\end{IEEEeqnarray}

E. Equation Numbering

Like \eqnarray,\IEEEeqnarray, has a “star form,” \IE

EEeqnarray*, which does not place equation numbers at the

end of each row by default. The default behavior of individual

rows can be overridden by placing the commands \IEEEye

snumber or \IEEEnonumber as needed in the last column.

\IEEEeqnarray also provides \IEEEyessubnumber and \I

EEEnosubnumber which can be used to enable or disable

a subequation number for the given row. To support this

feature, IEEEtran defines its own IEEEsubequation counter

(reset with changes to equation) and \theIEEEsubequati

on command.14

As of version 1.8 of IEEEtran, the star forms \IEEEyesn

umber*,\IEEEnonumber*,\IEEEyessubnumber*and \I

EEEnosubnumber*are available which persist across rows

until countermanded by another star command. The behavior

of later individual rows can be selectively overridden with the

use of the non-star forms as needed.

Despite there being four numbering commands, it is useful

to remember that there are only three IEEEeqnarray numbering

modes:

1) Display nothing and do not alter the counters (\IEEEn

onumber);

2) Increment the equation counter and display an equation

number without a subequation part (\IEEEyesnumber);

3) Increment the subequation counter and display an equa-

tion number with a subequation number (\IEEEyessu

bnumber).

\IEEEnosubnumber is not really needed and behaves much

like \IEEEyesnumber except that the former does not also

enable equation numbering if it isn’t already on (and does not

alter the numbering properties of the current row if equation

numbering is off).

Generally speaking, only one numbering command should

be used per row. In particular, mixing yes and no commands

on a single row could result in unintended operation. However,

a notable exception is the very useful \IEEEyesnumber\IEE

Eyessubnumber combination which starts a new subequation

sequence. For example,

\begin{IEEEeqnarray}{c}

x1\IEEEyesnumber\IEEEyessubnumber*\\

x2\\

x3\IEEEyesnumber\IEEEyessubnumber\label{eqn:expl}\\

x4\\

x5\IEEEyesnumber*\\

x6

\end{IEEEeqnarray}

yields:

x1(8a)

x2(8b)

x3(9a)

x4(9b)

x5(10)

x6(11)

14What is actually displayed is the \theIEEEsubequationdis com-

mand.

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The \IEEEyesnumber command increments the equation

counter of what would otherwise have been a subequation

row, resets the subequation counter and turns off subequation

numbering. The following \IEEEyessubnumber then incre-

ments the subequation counter by one and restores subequation

numbering.15

Note that any labels for (sub)equations must be placed

after any numbering control command(s) because, prior to that

point, the label will reference the equation number that would

have been used if there had not been any numbering control

commands.

Please be aware that \IEEEeqnarray, like \eqnarray,

will, if the equation is long enough, overwrite the equation

number without warning!16 For cases when this happens, users

can insert a \IEEEeqnarraynumspace command at the end

of the line (after any \IEEEyessubnumber if used) which

will insert a space equal in width to the displayed equation

number:

··· + x_z \IEEEyessubnumber\IEEEeqnarraynumspace\\

As a result, the entire multiline equation will be slightly shifted

to the left. The IEEE often does the same thing in its journals

when confronted by this situation. If an overfull hbox results,

the offending equation line will have to be further divided.

F. Extra Vertical Spacing and Page Breaks

Like \eqnarray,\IEEEeqnarray’s \\ command supports

a star form which inhibits page breaks at the given line as well

as an optional extra vertical spacing argument:

&+\:a + b\\*[5pt]

Users are reminded from Section IX that amsmath will

configure L

A

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E

X to disallow page breaks within multiline

equations—including those made by \IEEEeqnarray be-

cause it also honors the value of \interdisplaylinepen

alty.

Also like \eqnarray,\IEEEeqnarray normally places

a small amount of extra spacing (as specified by the length

command \jot) between lines to “open up” equations as well

as to prevent large symbols from coming to close to the lines

above them.

G. IEEEeqnarraybox

\IEEEeqnarray is not suitable for producing structures

such as matrices and tables because it must have exclusive

access to the main text column and cannot be nested within

other structures. For these applications, the \IEEEeqnarray

15Invoking only a \IEEEyessubnumber following a normal equation

number line will result in a sequence like 14, 14a. The IEEE does not typically

use normal equation numbers followed by subequations carrying that same

base equation number, but the capability is there if you ever need it. IEEEtran

versions prior to v1.8 differed here in that they automatically advanced the

equation number on the “first” call to \IEEEyessubnumber and so did

not have this degree of flexibility.

16This behavior is extremely difficult to avoid if the equation line is to

remain centered irrespective of the width of the equation number—without

even considering the subjective question of how close is too close for any

given case!

box command is provided. \IEEEeqnarraybox differs from

\IEEEeqnarray in the following ways:

1) the entire contents are wrapped within a box and there-

fore, can be nested within other display or alignment

structures (such as \equation,\IEEEeqnarray or

even another \IEEEeqnarraybox). Note that, like all

box structures, page breaks are not allowed between the

rows of an \IEEEeqnarraybox;

2) the default glue at the outer ends of the first and last

columns is 0 pt (“-”), not “+” centering glue as with \I

EEEeqnarray;

3) no automatic (hidden) equation number column is pro-

vided;

4) the star form “\IEEEeqnarraybox*” turns off the extra

\jot vertical spacing after each row;

5) \IEEEeqnarrayboxdecl is the global control.

There are two subforms: \IEEEeqnarrayboxm which is for

use within math modes and is analogous to \array; and \IE

EEeqnarrayboxt which is for use within text modes and is

analogous to \tabular. If called via \IEEEeqnarraybox the

current math/text mode will be auto-detected and the proper

subform will automatically be selected. Therefore, \IEEEeqn

arraybox can replace \array as well as \tabular.

The syntax for \IEEEeqnarraybox is similar to \IEEEeq

narray, but with two additional optional arguments:

\begin{IEEEeqnarraybox}[decl][pos][width]{cols}

.

\end{IEEEeqnarraybox}

The pos argument can be one of t,c, or bto control where the

box will be vertically aligned relative to the current baseline:

tat the top row; cat the center;17 bat the bottom row. The

default is b.

The width argument specifies the width the box. Warning:

if a width is specified, there must be one or more rubber

lengths in the inter-column glue specifiers (such as that of “*”

or “+”) so that the box can be sized as needed. If there is no

such glue, or the glue provided cannot stretch/shrink enough

as needed, the box cannot be sized to width and an underfull

or overfull hbox error will result. If no width argument is

provided, the box will be set to its natural width (and the use

of rubber inter-column glue will not be required).

\IEEEeqnarraybox uses the same column and glue type

specifiers/definitions as \IEEEeqnarray.

H. Line Spacing in L

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Before discussing some of the more advanced aspects of

vertical spacing control in the IEEEeqnarray family, it is im-

portant to review the details of L

A

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X’s line spacing algorithm.

Normally, baselines are separated by the amount given by the

length command \baselineskip. With each change in font

size, \baselineskip is reset to the default value for that font

size (multiplied by \baselinestretch). Then the value of

\baselineskip is saved to the length variable \normalbas

17Centering is actually done along the “math axis” (not exactly on the text

baseline, but quite close to it). Many L

A

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distinction.

SHELL: HOW TO USE THE IEEETRAN L

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elineskip (so that the normal value can be later referenced

even if \baselineskip is set to another value by the user).

However, if the top of a line ever gets closer than \lineski

plimit to the bottom of the line above it, the use of \basel

ineskip will be suspended and \lineskip spacing will be

placed between the two lines.18

This system works well for text. However, for mathematics,

whose symbols have a much higher dynamic range of heights

and depths, it is usually better to go ahead and always add an

extra fixed amount of space (\jot) as mentioned in Appendix

F-F.

When the IEEEeqnarray family is loaded, a new length

command is defined, \IEEEnormaljot, which stores the

nominal value of \jot19, so that this can be always be referred

to even if other values are currently being used.

At the start of \IEEEeqnarray/box, but before the local

or global controls, the following initialization takes place:

\lineskip=0pt

\lineskiplimit=0pt

\baselineskip=\normalbaselineskip

\jot=\IEEEnormaljot

Thus, \baselineskip is set to the normal value for the

current font, \jot is restored to its nominal value and the

\lineskiplimit system is disabled.20

This system is designed to better facilitate nested IEEEeq-

narraybox structures as well as to help prevent the user from

encountering seemingly uncontrollable spacing behavior (e.g.,

“How do I get rid of that unwanted space?!”).

I. The IEEEeqnarray Strut System

When creating tables, especially tables with vertical rules,

vertical space between the rows of the table is not generally

desirable because such space will suspend the column cell

definitions and “cut across” any vertical rules that may be

present. Yet, there must be a way to keep rows adequately

spaced apart. To solve this problem, the IEEEeqnarray/box

commands provide an integrated system to manage struts21

contained in a hidden column on the right end of each

IEEEeqnarray/box structure.

The struts in each row will be set to a default strut height

and depth. Normally, the default strut height and depth are

initialized to zero, so the struts will effectively not be present.

The user can set the default strut values via the

\IEEEeqnarraystrutsize{height}{depth}[decl]

command which can be placed in a local or global control. The

optional argument is for commands that will be executed prior

to the evaluation of the height and depth arguments. Thus,

\IEEEeqnarraystrutsize{0.5\baselineskip}{}[\large]

will set the default strut height to half the baselineskip used by

the large font size, even if the current baselineskip (and/or font

18Within IEEEtran.cls, \lineskiplimit and \lineskip are zero—if

things get too close it is the author’s responsibility to correct the problem

without having IEEEtran.cls second guessing the author’s intent.

19Within IEEEtran.cls, the nominal value of \jot is 25% of the baseli-

neskip for the normalsize font.

20As long as rows cannot be of negative height.

21“Struts” are vertical rules of zero width, but of finite height.

size) is different. The commands which are executed within the

optional argument are contained within their own environment

so as not to have any effects outside of the \IEEEeqnarra

ystrutsize command. For mimicking the action of \bas

elineskip, the typically recommended height and depth of

struts is 70% and 30%, respectively, of \normalbaselines

kip22.\IEEEeqnarraystrutsize will assume these values

if its height and/or depth arguments are left blank. e.g., in the

previous example, the strut depth will be set to 30% of \nor

malbaselineskip for the large font size.

There is also a

\IEEEeqnarraystrutsizeadd{height}{depth}[decl]

command which will add to the current default strut values

and can be used much like the \extrarowheight parameter

of the array.sty package. Empty arguments are assumed to be

0 pt.

\IEEEeqnarraystrutsize and \IEEEeqnarraystruts

izeadd can also be used at the end of the last column to alter

the strut size used for a particular row (the default strut values

of the other rows will not be affected).

There is also a

\IEEEstrut[height][depth][decl]

which produces a strut. It can be used whenever a “manual”

strut is needed—even outside the \IEEEeqnarray/box en-

vironments. If a height or depth argument is not provided (or

empty) then these will be assumed in the same way as \IEEE

eqnarraystrutsize does.

For diagnostic purposes (in order to see if any row objects

exceed the height of the struts), the command \IEEEvisibl

estrutstrue can be placed with an \IEEEeqnarray/box

or \IEEEstrut control to make the struts visible.

When using \IEEEeqnarraybox to produce tables that

contain vertical lines, it is usually desirable to shutdown the

\baselineskip system and switch over to pure strut spacing.

The following command sequence, placed within a local or

global control, will serve this purpose:

\IEEEeqnarraystrutsize{0.7\normalbaselineskip}{0.3\n

ormalbaselineskip}[\relax]

\setlength{\baselineskip}{0pt}%

\setlength{\lineskip}{0pt}%

\setlength{\lineskiplimit}{0pt}%

\setlength{\jot}{0pt}%

Note the use of “%” to prevent the ends of the lines that end

in braces from being interpreted as unwanted spaces. Because

of the frequent need to call this sequence, the IEEEeqnarray

family provides the \IEEEeqnarraystrutmode command

which does the same thing.

J. Overriding Column Types

Within a row, one or more column types can be overridden

by placing the command

\IEEEeqnarraymulticol{num_cols}{col_type}{text}

22Note that this not the normalsize baselineskip, but the normal baselineskip

for the current font size.

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as the very first command in a cell. This command is the

IEEEeqnarray equivalent of \multicolumn. The first argu-

ment is the number of columns to override (cutting through

any inter-column glues as needed). The second argument is the

column type specifier to use. The third argument contains the

cell text. The third argument will have to be enclosed within

an extra set of braces if the column type is to acquire it as an

argument—as was done with the “myp” parbox column type

in the example earlier (Appendix F-B).

There is also the \IEEEeqnarrayomit command which,

when used as the very first command in a cell, will suspend the

use of the normal column type for that cell. This is somewhat

like a quicker version of \IEEEeqnarraymulticol{1}{x}

{}.

Users are cautioned not to use commands like these (e.g.,

\multicolumn) that are designed for other alignment envi-

ronments.23

K. Predefined Column Types for Rules

Several of the predefined column types produce vertical or

horizontal lines. Note that, in the IEEEeqnarray family, rules

are declared and treated as normal column types—they are not

hidden. Although this approach may increase the number of

columns the user has to keep track of, especially when creating

tables, it does offer a great deal of flexibility by allowing the

user to override, or otherwise manipulate, any column type

(including those that produce rules) at will.

All of the predefined rule column types use the \arrayru

lewidth length to determine the line thickness and \doubl

erulesep for the spacing of double rules.

The “v” column type produces a vertical rule, “vv” produces

two back-to-back vertical rules which will appear as one

rule of twice the normal thickness. “V” produces a double

vertical rule with \doublerulesep spacing between its two

lines. “VV” produces two back-to-back double vertical rules

which will appear to be three vertical rules, the middle one of

which being twice as thick as the other two. It is possible to

“spread apart” the “vv” and “VV” types by placing a spacer

within their columns—thus they can be used to generate two

single, or double, vertical rules whose separation distance is

programmable.

The “h” and “H” types produce single and double horizontal

rules, respectively. Horizontal rule types are not normally used

in the column specifications, but rather with the \IEEEeqna

rraymulticol command in order to draw a horizontal rule

across one or more column(s).

Please be aware that the line commands of other alignment

environments may not work properly within the IEEEeqnarray

family which provides its own ways of doing these types of

things. In particular, \cline is totally incompatible—users

should use the \IEEEeqnarraymulticol{num_cols}{h}

{} command instead. However, \vline and \hline should

work—unless another L

A

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X package redefines them in some

23Those who are familiar with T

E

X may be interested in the fact that T

E

X’s

\omit,\span and \multispan should work in \IEEEeqnarraybox,

but not in \IEEEeqnarray because of the need to track column usage with

a hidden counter in the latter.

incompatible way. The IEEEeqnarray family provides its own

version of \vline:

\IEEEeqnarrayvrule[rule_thickness]

that produces a vertical rule extending from the top to bottom

of a cell without overriding the column type. The optional

argument is for specifying the rule thickness which defaults

to \arrayrulewidth if no argument is provided.

The IEEEeqnarray row commands (discussed in the next

section) provide some alternatives to \hline.

L. Row Commands

The IEEEeqnarray family has several commands which can

be used to produce special rows that span all the columns.

Unless otherwise noted, the commands described here must

issued as the very first command in a given row.

To produce a spacer row that relies on the strut system, use

\IEEEeqnarrayseprow[height][decl]

The first argument specifies the height of the strut row, if left

blank or empty, the default value of 0.25\normalbaseli

neskip will be assumed. The second optional argument is

for commands which will be executed prior to the evaluation

of the first argument as is done with \IEEEeqnarraystrut

size.\IEEEeqnarrayseprow will not interrupt the column

definitions, so it will not cut vertical lines. If column definition

suspension is desired, use the cutting form which will override

all the column types in the entire row:

\IEEEeqnarrayseprowcut[height][decl]

To produce a horizontal rule row, use:

\IEEEeqnarrayrulerow[rule_thickness]

which will override all the column definitions with one that

produces a horizontal rule. If the optional rule thickness is not

specified, the value of \arrayrulewidth will be used.

To produce a double rule row, use:

\IEEEeqnarraydblrulerow[rule_thickness][spacing]

which will produce a rule row, a (noncutting) separation row,

followed by another rule row. If the optional rule thickness is

not specified, the value of \arrayrulewidth will be used

when producing each of the two rule rows. If the optional

separation distance is not specified, the value of \doubleru

lesep will be used. There is also a cutting form:

\IEEEeqnarraydblrulerowcut[rule_thickness][spacing]

which works the same way except that the separation row

will override all the column definitions. (Vertical rule columns

will not appear inside the double rule row produced by this

command.)

M. Useful Low Level T

E

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Although the use of lower level T

E

X commands is generally

frowned upon in L

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X, some of them are just too helpful to

ignore.

\phantom{} produces an invisible box with the width,

height and depth of its contents, but the contents themselves

SHELL: HOW TO USE THE IEEETRAN L

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will not appear in the output. There is also the \hphantom

{} and \vphantom{} forms which retain only the contents’

width, or its height and depth, respectively. As an example,

look carefully at the footnotes at the bottom of Table V. This

table was produced using the \IEEEeqnarraybox command.

The footnotes are actually contained within the last two rows

of the table. Note how the left sides of the footnotes line

up, even though the first one has a superscript asterisk for a

footnote symbol. The reason that the second row lines up is

because, at its left side, it employs a horizontal phantom of

the very same symbol:

\hphantom{\textsuperscript{*}}

Vertical phantoms can be used to equalize row height or

spacing—such as to get matrices that fit within brackets of

the same size even though one has “tall” symbols and the

other not.

The opposite of \hphantom{} is \rlap{} which displays

its contents, but with zero width. There is also an \llap{}

which does the same thing, but the contained object will appear

just to the left of the given point, rather than after as with

\rlap. For example, look closely at the first “Width” column

heading in Table V. The word “Width” is centered irrespective

of the asterisk. That is because the width of the asterisk was

zeroed:

Width\rlap{\textsuperscript{*}}

The vertical analog of \rlap is \smash{} which reduces the

apparent height and depth of its contents to zero. (L

A

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X’s

\raisebox{0pt}[0pt][0pt]{} does about the same thing,

and also provides an adjustable vertical offset.) \smash can

be used when space is already reserved for an object, but

that L

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X does not “know” this and would allocate unwanted

additional vertical space. One good use of smash for table

objects that are to be “slipped” into a hidden row of zero

height, or into a row which is to be no higher than the “short”

things, such as horizontal rules, that are in its other columns.

The T

E

X\noalign{} command can be used within IEEEe-

qnarray family to inject text which is outside of the alignment

structure. For example,

\begin{IEEEeqnarray}{rCl}

A_1&=&7\IEEEyesnumber\IEEEyessubnumber\\

A_2&=&b+1\IEEEyessubnumber\\

\noalign{\noindent and\vspace{\jot}}A_3&=&d+2\IEEEye

ssubnumber%

\end{IEEEeqnarray}

produces

A1= 7 (12a)

A2=b+ 1 (12b)

and

A3=d+ 2 (12c)

When employed, \noalign must be the very first com-

mand in a row—even before any \IEEEeqnarraymulticol,

\IEEEeqnarrayomit, or row commands.

Be forewarned that the proper use of \noalign can be

tricky. There are three potential issues. (1) Remember that

\noalign will place its contents outside of the alignment.

So, the line spacing controls of the IEEEeqnarray commands

will not be in effect. The user may have to manually add \bas

elineskip and/or \jot spacing as needed (which was done

in the previous example). (2) Furthermore, \noalign does

not automatically place its contents within a box. However,

nonaligned material must be placed within a horizontal box

when within the vertical box produced by the \IEEEeqnarr

aybox command. Therefore, when using \noalign within

a\IEEEeqnarraybox, be sure to wrap things up in an

\hbox{}:24

\noalign{\hbox{and therefore}}

(3) Finally, there may be some issues related to how easily

page breaks occur around the \noalign lines. This is an issue

only with \IEEEeqnarray because page breaks cannot occur

within the box produced by \IEEEeqnarraybox. If needed,

page break desirability can be altered by manually entering

\pagebreak, or \nopagebreak, etc., at the end of the \no

align contents.

N. More Practical Examples of Use

The use of the IEEEeqnarray is somewhat complicated.

However, once the building blocks and core concepts are

understood, the user may find that is easier to use the

IEEEeqnarray family for just about every alignment situation

rather than to have to remember all the interfaces and unique

behaviors of many different tools.

A few “real world” examples will now be demonstrated.

1) IEEEeqnarray Cases Structures: Cases structures can be

obtained using \IEEEeqnarraybox:

|x|=x, for x≥0

−x, for x < 0(13)

which was produced using the code:

\begin{equation}

\setlength{\nulldelimiterspace}{0pt}

|x|=\left\{\begin{IEEEeqnarraybox}[\relax][c]{l’s}

x,&for $x \geq 0$\\

-x,&for $x < 0$%

\end{IEEEeqnarraybox}\right.

\end{equation}

Note the use of the large \quad (1 em) spacing before the

conditional statements. The zeroing of \nulldelimiterspa

ce, an optional step, eliminates the width of the nonvisible

closing brace “\right.” in order to perfectly center the

visible portion of the equation.25

Note that both branches share a common equation number.

If an equation (sub)number is wanted for each branch, the

preferred solution is to use the cases.sty package as discussed

in Section IX-A. However, it is possible to use \IEEEeqnar

ray to build such a thing—although it takes extra work and

a few tricks to do so. For example,

x, for x≥0(14a)

|x|=−x, for x < 0(14b)

24L

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25The width of null delimiters is typically only 1.2 pt, and so can usually

be safely ignored.

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was produced using the code:

\begin{IEEEeqnarray}[\setlength{\nulldelimiterspace}

{0pt}]{rl’s}

&x,&for $x \geq 0$\IEEEyesnumber\IEEEyessubnumber\\*

[-0.625\normalbaselineskip]

\smash{|x|=\left\{\IEEEstrut[3\jot][3\jot]\right.}&&

\nonumber\\*[-0.625\normalbaselineskip]

&-x,&for $x < 0$\IEEEyessubnumber

\end{IEEEeqnarray}

A hidden middle row is used to hold the left hand side of

the equality. In order to prevent this row from altering the

spacing between the two branches, its height must be smashed

and the extra line spacing (which consists of \baselinesk

ip, plus \jot which is normally 0.25\baselineskip for

IEEEtran.cls.) must be removed, half from above and half

from below,—making it look as though the middle row never

occurred. Because the large brace cannot “see” the height of

the branches, it must be manually sized with a strut. The

star form of the new line commands is used to prevent the

possibility of a page break within the structure.

2) Matrices: Displayed matrices can easily be created with

\IEEEeqnarraybox:

I= 100

010

001!(15)

The code of this example is quite simple:

\begin{equation}

I = \left(\begin{IEEEeqnarraybox*}[][c]{,c/c/c,}

1&0&0\\

0&1&0\\

0&0&1%

\end{IEEEeqnarraybox*}\right)

\end{equation}

Because the example matrix has elements of normal height,

one can use the star form of \IEEEeqnarraybox to turn off

the extra \jot component of the line spacing so as to make

a more compact matrix. If larger symbols had been used in

the matrix, the nonstar form would be the better choice. \ar

raycolsep typically serves quite well as an element column

separator. A standard small math space is added to the ends

of the matrix to provide a little distance between it and its

enclosing parentheses.

It is instructive to show how to construct a “small” matrix26,

S=h1/2 0

0 3/4i(16)

which was produced via

\newcommand{\mysmallarraydecl}{\renewcommand{%

\IEEEeqnarraymathstyle}{\scriptscriptstyle}%

\renewcommand{\IEEEeqnarraytextstyle}{\scriptsize}%

\renewcommand{\baselinestretch}{1.1}%

\settowidth{\normalbaselineskip}{\scriptsize

\hspace{\baselinestretch\baselineskip}}%

\setlength{\baselineskip}{\normalbaselineskip}%

\setlength{\jot}{0.25\normalbaselineskip}%

\setlength{\arraycolsep}{2pt}}

%

\begin{equation}

S=\left[\begin{IEEEeqnarraybox*}[\mysmallarraydecl]

26IEEE authors should note that the use of small matrices is not recom-

mended as the IEEE does not usually reduce font sizes in equations or alter

the main text baselineskip to accommodate in-text mathematics.

TABLE VI

NETWORK DELAY AS A FUNCTION OF LOAD

Average Delay

βλmin λmax

1 0.057 0.172

10 0.124 0.536

100 0.830 0.905*

*limited usability

[c]{,c/c,}

1/2&0\\

0&3/4%

\end{IEEEeqnarraybox*}\right]

\end{equation}

The use of a user defined command, \mysmallarrayde

cl, to contain the IEEEeqnarray setup code, demonstrates

how users can easily recreate their most commonly used

structures by fully exploiting the on-the-fly configurability of

the IEEEeqnarray family.

This example is more complex than need be in order to

demonstrate a few techniques. It would be easy enough to set

\baselineskip to the desired value, but suppose that the

matrix rows are to be spaced some multiple of the \baselin

eskip of the \scriptsize font. Complicating matters even

more is the fact that most L

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user to execute text font size commands within math mode—

and the matrix is within an equation. So, \scriptsize cannot

be used to directly set the \baselineskip.

The first step is to set the math and text columns to

their desired styles. Then \baselinestretch is setup to be

used like \arraystretch. The trick is to run \scriptsize

within a \settowidth command which stores the \basel

ineskip of the \scriptsize font, multiplied by \baseli

nestretch, in \normalbaselineskip which is then used

to set \baselineskip,\jot, etc. Finally, \arraycolsep is

reduced to better suit the smaller font. Note the use of “%”

to prevent unwanted spaces from appearing after the braces at

the end of lines in \mysmallarraydecl.

3) Tables: Tables, especially those with lines, tend to be a

little more complicated. Table VI was made with the following

code:

\begin{table}[!t]

\centering

\caption{Network Delay as a Function of Load}

\label{table_delay}

\begin{IEEEeqnarraybox}[\IEEEeqnarraystrutmode\IEEEe

qnarraystrutsizeadd{2pt}{0pt}]{x/r/Vx/r/v/r/x}

\IEEEeqnarraydblrulerowcut\\

&&&&\IEEEeqnarraymulticol{3}{t}{Average Delay}&\\

&\hfill\raisebox{-3pt}[0pt][0pt]{$\beta$}\hfill&&\IE

EEeqnarraymulticol{5}{h}{}%

\IEEEeqnarraystrutsize{0pt}{0pt}\\

&&&&\hfill\lambda_{\mbox{min}}\hfill&&\hfill

\lambda_{\mbox{max\vphantom{i}}}\hfill&\IEEEeqnarray

strutsizeadd{0pt}{2pt}\\

\IEEEeqnarraydblrulerowcut\\

&1&&& 0.057&& 0.172&\\

&10&&& 0.124&& 0.536&\\

&100&&& 0.830&& 0.905\rlap{\textsuperscript{*}}&\\

\IEEEeqnarraydblrulerowcut\\

&\IEEEeqnarraymulticol{7}{s}{\scriptsize\textsupersc

SHELL: HOW TO USE THE IEEETRAN L

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X CLASS 27

TABLE VII

POSSIBLE ΩFUNCTIONS

Range Ω(m)

x < 0 Ω(m) =

m

X

i=0

K−i

x≥0 Ω(m) = √m

ript{*}limited usability}%

\end{IEEEeqnarraybox}

\end{table}

Because this table has lines, the first step is to enable strut

mode line spacing. The strut height is then increased by a

couple of points to provide a little more headroom above the

letters.27 This table uses cutting horizontal rules and open

sides as is commonly done in IEEE publications. There are

three extra “x” columns which serve as place holders. The

“x” columns at each end serve as a quick way to get the

horizontal rules to extend a little past the contents of the table.

The middle “x” column serves as an attachment point for the

horizontal rule that is below “Average Delay”. Without this

extra column, the left side of that horizontal rule would cut

into the middle double vertical rule.28 Notice how the “β” is

smuggled in as part of the row containing the horizontal rule.

βhas to be smashed so that it will not add unwanted vertical

spacing. Likewise, the strut for that row is disabled. Also, \ra

isebox is used instead of \smash so that βcan be vertically

lowered—otherwise it would appear on its baseline which is

too high for the purpose at hand. The \hfill on either side

of βchanges the justification of that cell to centered. The

“min” and “max” subscripts would not normally sit at the

same level because the “i” in min is slightly higher than the

letters in “max”. To fix this, a \vphantom “i” is added to

“max”. Because these subscripts sit so low, the depth of that

line’s strut is increased a couple of points. Alternatively, one

could have just smashed the “i”. The asterisk next to “0.905”

is reduced to zero width via \rlap so that it will not affect its

cell’s width or alignment. This example also illustrates how

to integrate table footnotes into the end of a table without the

help of external packages.

Strut spacing does not work so well for rows that contain

tall symbols because such objects routinely exceed the height

of the struts. Furthermore, increasing the strut height is often

not an option because (1) the height and depth of the tall

symbols must be measured or guessed; and (2) there may be

other rows which have normal line height. Table VII illustrates

such a situation. Its code is shown here:

\begin{table}[!t]

\centering

\caption{Possible $\Omega$ Functions}

\label{table_omega}

\begin{IEEEeqnarraybox}[\IEEEeqnarraystrutmode\IEEEe

qnarraystrutsizeadd{2pt}{1pt}]{v/c/v/c/v}

\IEEEeqnarrayrulerow\\

&\mbox{Range}&&\Omega(m)&\\

27Knuth calls this extra step a mark of quality.

28Some may even think it would be better that way, but we want to show

some tricks in these examples.

\IEEEeqnarraydblrulerow\\

\IEEEeqnarrayseprow[3pt]\\

&x < 0&&\Omega(m)=\sum\limits_{i=0}^{m}K^{-i}&\IEEEe

qnarraystrutsize{0pt}{0pt}\\

\IEEEeqnarrayseprow[3pt]\\

\IEEEeqnarrayrulerow\\

\IEEEeqnarrayseprow[3pt]\\

&x \ge 0&&\Omega(m)=\sqrt{m}\hfill&\IEEEeqnarraystru

tsize{0pt}{0pt}\\

\IEEEeqnarrayseprow[3pt]\\

\IEEEeqnarrayrulerow

\end{IEEEeqnarraybox}

\end{table}

The solution is to use \IEEEeqnarrayseprow to manually

add in a fixed amount of extra space as needed. In this way,

\IEEEeqnarrayseprow can do for lined tables what \jot

does for multiline equations. Of course, using this method, the

baselines of the rows will no longer be equally spaced.

The \hfill in the square root cell is a cheap, but effective,

way of getting the equal signs to line up without the need of

additional columns.

ACKNOWLEDGMENT

The author would like to thank Ken Rawson, Kevin

Lisankie, Kimberly Sperka, Steve Wareham, Patrick Kellen-

berger, Laura Hyslop and Cathy Cardon of the IEEE for their

help and support in making this work possible. The knowledge

and prior work of T

E

X gurus such as Donald Arseneau,

Fred Bartlett, David Carlisle, Tony Liu, Frank Mittelbach,

Piet van Oostrum, Roland Winkler and Mark Wooding were

instrumental in developing the complex IEEEeqnarray family

of commands. The author is also grateful to Peter Wilson and

Donald Arseneau for allowing the inclusion of their \@ifmt

arg command.

Finally, this work might not have been possible had it

not been for the efforts of the prior IEEEtran developers:

Gerry Murray, Silvano Balemi, Jon Dixion, Peter Nüchter and

Juergen von Hagen. Their work still lives on to some degree

within IEEEtran.

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Michael Shell (M’87) received the B.E.E., M.S.E.E.

and Ph.D. degrees in electrical engineering all from

the Georgia Institute of Technology, Atlanta, in

1991, 1993 and 2004 respectively. He has developed

several all-optical packet-switched network subsys-

tems and node demonstrations. His research interests

include all-optical packet-switched networks, high

speed opto-electronic interface design, discrete sim-

ulation and exact Markov models for buffered packet

switches.

Dr. Shell is also the author of the most recent

versions of the IEEEtran L

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X class and BIBT

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X style packages and is the

current maintainer of both.