# Change font size in Siam's Latex macros

I would like to print the current draft of a paper I'm writing with a bigger font size, say 12pt. Unfortunately the usual 12pt option doesn't work.

Any suggestions?

• Apparently in the .cls file the line that loads the size file is commented: `%%%%%%%%%%%%%%%%%\input{siam1\@ptsize.clo}` and the font size is hardcoded later on. – Phelype Oleinik Jul 19 '18 at 23:38
• @PhelypeOleinik I'm not familiar with macros. What should I then change in the .cls files to change the font size? – F.M.R. Jul 20 '18 at 0:53
• Welcome to TeX.SX! You could issue a `\large` immediately after the title. This is because the class file defines `\newcommand{\large}{\@setfontsize\large\@xiipt{14}}`. But as @PhelypeOleinik pointed out, the font size is hard-coded and the options `10pt`, `11pt` and `12pt` don’t do anything. – Ruixi Zhang Jul 20 '18 at 1:25

A word of advice: if you are going to submit a paper to this SIAM, then it's better if you don't change the font size. If, on the other hand, you are submitting this somewhere else, it's best if you don't use this class.

But, if anyhow you decide to proceed...

At the line 175 of `siamart171218.cls` you can see:

``````% eliminate siam10.clo altogether:
%%%%%%%%%%%%%%%%%\input{siam1\@ptsize.clo}
``````

At some point in time this class apparently used to load a size definition file `siam10.clo`, but this was deprecated because the `12pt` option would cause the class to load `siam12.clo` which, from a quick Google search, I deduced never existed, so an error would occur. So, to avoid unnecessary errors, the maintainers eliminated the size options and hardcoded the `10pt` size.

But what to do to change this?

The `siam10.clo` (that can be found here) was derived from LaTeX's `size10.clo`. You could use LaTeX's `size12.clo` to build a `siam12.clo`. This will take a while to do until you tweak every size to make it look right. But it's not impossible.

Or, if you don't mind the minimalisms, you can use `size12.clo` instead of `siam12.clo`.

Once you have the `siam12.clo` (or any other size file), you can load it after you load the class:

``````\documentclass{siamart171218}
\makeatletter
\let\small\@undefined% We have to un-define the font sizes
\let\footnotesize\@undefined
\let\scriptsize\@undefined
\let\tiny\@undefined
\let\large\@undefined
\let\Large\@undefined
\let\LARGE\@undefined
\let\huge\@undefined
\input{siam12.clo}% Then load the size file (can be any other, like size12.clo)
\makeatother
``````

This is the least-modification workaround. There might be some inconsistencies, but then again, you would have to tweak the size file to make the article look right.

Someone might be wondering, why did I choose to un-define the sizes then load another size file, instead of changing the `.cls`. I thought this is the best way around because the class file does some things in the middle of the code that should belong to the size file, so to avoid making mistakes, I thought this is the best way to do it.