Math & ScienceHow to align Items in a Sum?

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Cham
Posts: 937
Joined: Sat Apr 02, 2011 4:06 pm

How to align Items in a Sum?

Post by Cham »

I'm having a small alignment problem with the idex of a sum :

Code: Select all

\sum_{\substack{i,\, j \,=\, 1 \\ j \, \ne \, i}} A_{ij}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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The = and \ne signs aren't properly aligned. How should we modifity that code to align the items properly ?
Last edited by Cham on Wed Jun 22, 2011 10:47 pm, edited 1 time in total.

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localghost
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Posts: 9202
Joined: Fri Feb 02, 2007 12:06 pm

How to align Items in a Sum?

Post by localghost »

You can insert a vertical phantom, that is to say an appropriate box with hidden content.

Code: Select all

Code, edit and compile here:
\documentclass[11pt,a4paper]{article}
\usepackage{amsmath}
\begin{document}
\[
\sum_{\substack{i,\, j\,=\, 1 \\ \hphantom{i,} j\,\ne\, i}} A_{ij}
\]
\end{document}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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Thorsten
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Cham
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Joined: Sat Apr 02, 2011 4:06 pm

How to align Items in a Sum?

Post by Cham »

localghost wrote:You can insert a vertical phantom
I tried it. The alignment isn't perfect.
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localghost
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Re: How to align Items in a Sum?

Post by localghost »

Works fine for me. Please clarify in which way this is not satisfactory.
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Cham
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Joined: Sat Apr 02, 2011 4:06 pm

How to align Items in a Sum?

Post by Cham »

localghost wrote:Works fine for me. Please clarify in which way this is not satisfactory.
The "=" and "\ne" aren't exactly aligned. If you compile and watch the index closely, you'll notice a small (and noticeable) offset. It's ugly.
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localghost
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Re: How to align Items in a Sum?

Post by localghost »

I can't comprehend this.
Attachments
The rendered output of the provided code.
The rendered output of the provided code.
sum-index.png (4.96 KiB) Viewed 11604 times
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Stefan Kottwitz
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How to align Items in a Sum?

Post by Stefan Kottwitz »

Hi Cham,

since equations/inequalities have to be aligned at a relation symbol, you could use an aligned environment. Also here you can customize size and fine-tune spacing. For example:

Code: Select all

Code, edit and compile here:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\sum_{\scriptsize\begin{aligned}i, j &= 1 \\[-4pt] j &\ne i\end{aligned}} A_{ij}
\]
\end{document}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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Btw. Thorstens way with a phantom command is handy in many situations.

Stefan
LaTeX.org admin
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Cham
Posts: 937
Joined: Sat Apr 02, 2011 4:06 pm

How to align Items in a Sum?

Post by Cham »

Stefan_K wrote:Hi Cham,

since equations/inequalities have to be aligned at a relation symbol, you could use an aligned environment. Also here you can customize size and fine-tune spacing. For example:

Code: Select all

Code, edit and compile here:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\sum_{\scriptsize\begin{aligned}i, j &= 1 \\[-4pt] j &\ne i\end{aligned}} A_{ij}
\]
\end{document}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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This code works fine. Thanks a lot for it !
User avatar
Cham
Posts: 937
Joined: Sat Apr 02, 2011 4:06 pm

How to align Items in a Sum?

Post by Cham »

I'm getting some warning messages in the log file about the previous formula :
LaTeX Font Warning: Command \scriptsize invalid in math mode on input line 222.
The formula associated to this warning message is this :

Code: Select all

\sum_{\scriptsize\begin{aligned} i, j &= 1 \\[-4pt] i &\ne j \end{aligned}}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
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Apparently, the \scriptsize command is not allowed, while the compiled formula is nicely looking on the PDF version. What's going on here ?

Is there a better way to code that double-sum, without getting that warning message ?
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