[Tex/LaTex] Alignment with IEEEeqnarray

equationshorizontal alignment

Let's say I wish to use IEEEeqnarray to typeset an equation like the following:
enter image description here

Obviously I can do this by manually inserting lots of spacing commands, but I would prefer to be able to do this by specifying the column alignment when the IEEEeqnarray environment is started. So I have been experimenting with various alignment options such as

\begin{IEEEeqnarray}{lCr}

but can I only achieve an equation typeset similar to
enter image description here

How can I do this through the allignment option?

Best Answer

Do you remember about ampersands?

\documentclass{article}
\usepackage{IEEEtrantools}


\begin{document}


\begin{IEEEeqnarray}{lCr}
  y&=&xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\\
 && {}+gggggggggggggggggggggg
\end{IEEEeqnarray}

\end{document}

enter image description here

Please observe not only big C for proper spacing around =, but also {} for proper spacing around + in the second line.

Related Solutions

[Tex/LaTex] Typesetting a pattern matching equation

Without an image of exactly how you want this typeset it is difficult to know for sure, but perhaps one of these is what you are looking for:

enter image description here

or perhaps:

enter image description here

\documentclass{book}
\usepackage{amsmath}
\newcommand{\fib}{\mathrm{fib}}

\begin{document}
\begin{align*}
    &\text{if }  x < 2 & \fib X &= 1 \\
    &\text{otherwise } & \fib X &= (\fib (X - 1)) + (\fib (X - 2))
\end{align*}
Another option is:
\begin{align*}
\fib X = \begin{cases}
    \text{if }  x < 2 & = 1 \\
    \text{otherwise } & = (\fib (X - 1)) + (\fib (X - 2))
\end{cases}
\end{align*}
\end{document}

Here is how you can modify the given MWE to obtain better spacing:

enter image description here

Notes:

@{} is used to eliminate the inter column spacing
I added {} before the = to get proper math spacing.
I replaced the $$ ... $$ with \[ ... \]. See Why is \[ ... \] preferable to $$ ... $$? for more details.
Changes as per egreg's suggestions:
1. \mathit{foreign}, \mathit{time\_of\_call} and \mathrm{head} for better appearance of the formulas.
2. Removed \, after \prodtime, and the other uses of \operatorname.

Code:

\documentclass{article}
\usepackage{amsmath}

\newcommand{\prodtime}{\operatorname{prodtime}}

\begin{document}
\[
\begin{array}{l l @{}l}
\prodtime V & X = Y                        &{}= 0 \\
\prodtime V & X = f(\ldots)                &{}= 0 \\
\prodtime V & p(X_1,\,\ldots,\,X_n)        &{}= \prodtime V\,(\operatorname{body} p) \\
\prodtime V & V = \,f(X_1,\,\ldots,\,X_n)  &{}= \prodtime V\,(\operatorname{body} f) \\
\prodtime V & X_0(X_1,\,\ldots,\,X_n)      &{}= \mathit{time\_of\_call} \\
\prodtime V & m(X_1,\,\ldots,\,X_n)        &{}= \mathit{time\_of\_call} \\
\prodtime V & \mathit{foreign}(\ldots)     &{}= 0 \\
\prodtime V & G_\mathrm{head},\,G_\mathrm{tail}
\end{array}
\]
\end{document}

[Tex/LaTex] IEEEeqnarray page breaks

By default IEEEtran class does allow breaks in equations across pages:

Bottom of page 1

Sample from page 1

Top of page 2

Sample from page

\documentclass{IEEEtran}

\begin{document}
Text.\newpage\vspace*{22cm}
A multiline display
\begin{IEEEeqnarray}{rCl}
  x &= &y\\
  p &= &q\\
  u &= &v
\end{IEEEeqnarray}

\end{document}

However, loading the amsmath package turns off this behaviour. The amsmath package provides \allowdisplaybreaks which can either be used document wide or applied to a single display as follows:

\documentclass{IEEEtran}

\usepackage{amsmath}

\begin{document}
Text.\newpage\vspace*{22cm}
A multiline display
{\allowdisplaybreaks
\begin{IEEEeqnarray}{rCl}
  x &= &y\\
  p &= &q\\
  u &= &v
\end{IEEEeqnarray}}

\end{document}

Which will give the same equation breaking across pages as before.

Note that IEEEeqnarraybox will never break accross pages.

Best Answer

Related Solutions

[Tex/LaTex] Typesetting a pattern matching equation

Notes:

Code:

[Tex/LaTex] IEEEeqnarray page breaks

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