# Adding vertical space in a multi-line equation while using IEEEeqnarray

how can I add vertical space between lines in an equation while using IEEEeqnarray?

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Please add a small example of your use of the ieeeeqnarray environment. Also, are you looking to change the space between successive lines globally or on a one-off basis? –  Mico Sep 18 '11 at 22:14
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## 4 Answers

I have never used gather, but if working within the array environment, just add vertical space to line jumps. It may work with gather.

If used often, define a new line jump command.

Example:

\documentclass{article}

\newcommand{\lj}{\vspace*{2mm}\\} % vertical space is added

\begin{document}

$\begin{array}{c} Line 1 \lj Line 2 \lj Line 3 \lj Line 4 \lj Line 5 \end{array}$

\end{document}

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a) This doesn't seem to address the particular question of the IEEE environments and b) in such an approach you would be better with \\[2mm] as in Gonzalo Medina's answer. –  Andrew Swann Sep 30 '13 at 13:43
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If you want to change the spacing for all the lines in the current IEEEeqnarray environment you can use:

\documentclass{IEEEtran}

\begin{document}{\setlength{\IEEEnormaljot}{15pt}%
\begin{IEEEeqnarray}{c}
a = b\\
c=d\\
e=f
\end{IEEEeqnarray}
}
\end{document}


Note the additional { which makes the setting local to this group and does not affect other IEEEeqnarray environments. Alternatively you could define your own environment that contains this setting:

\documentclass{IEEEtran}

\newenvironment{MyIEEEeqnarray}[1][c]{%
\setlength{\IEEEnormaljot}{15pt}%
\begin{IEEEeqnarray}{#1}%
}{%
\end{IEEEeqnarray}%
}%

\begin{document}
\begin{MyIEEEeqnarray}[c]
a = b\\
c=d\\
e=f
\end{MyIEEEeqnarray}
\end{document}


Here I made the [c] setting optional.

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I only want extra space for the lines of the equation itself. In other words, only part enclosed in \begin{IEEEeqnarray}... \end{IEEEeqnarray}. –  Isaac Kleinman Sep 18 '11 at 20:16
The above will ONLY affect spacing in the current IEEEeqnarray as it is in a group. –  Peter Grill Sep 18 '11 at 20:18
Actually, there is no need to wrap around the IEEEeqnarray environment. The \IEEEeqnarraydecl hook or the optional argument of the IEEEeqnarray environment can be used instead. –  mhp Sep 18 '11 at 20:56
@mhp: Thanks, I did not know about that. But I personally prefer to wrap it in an environment, as then it is going to be consistent across the entire document. –  Peter Grill Sep 18 '11 at 21:51
Settings specified in the \IEEEeqnarraydecl hook apply to every instance of the IEEEeqnarray environment in the document. You can override them for a single instance using the optional argument. Note furthermore that setting \IEEEnormaljot only works because \jot is initialized as \IEEEnormaljot in the standard set-up of the IEEEeqnarray environment. –  mhp Sep 19 '11 at 8:27
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You can set the \jot length in the \IEEEeqnarraydecl hook:

\documentclass{article}

\usepackage{IEEEtrantools}

\renewcommand*{\IEEEeqnarraydecl}{%
\setlength{\jot}{2\IEEEnormaljot}% twice the normal value of \jot
}

\begin{document}

\begin{IEEEeqnarray}{RCL}
a&=&b\\
x&=&y
\end{IEEEeqnarray}

\end{document}


Alternatively, you can set \jot in the optional argument of the IEEEeqnarray environment. Note that, in both cases, the change of \jot is only local.

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You can use the optional argument for \\:

\documentclass{IEEEtran}

\begin{document}

\begin{IEEEeqnarray}{c}
a = b\\[5pt]
c=d
\end{IEEEeqnarray}

\end{document}

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How can change the setting once for the entire equation? –  Isaac Kleinman Sep 18 '11 at 20:00
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