# Make SageTeX known to TeX¶

Sage is largely self-contained, but some parts do need some intervention to work properly. SageTeX is one such part.

The SageTeX package allows one to embed computations and plots from Sage into a LaTeX document. SageTeX is installed in Sage by default, but to use SageTeX with your LaTeX documents, you need to make your TeX installation aware of it before it will work.

The key to this is that TeX needs to be able to find sagetex.sty, which can be found in SAGE_ROOT/local/share/texmf/tex/generic/sagetex/, where SAGE_ROOT is the directory where you built or installed Sage. If TeX can find sagetex.sty, then SageTeX will work. There are several ways to accomplish this.

• The first and simplest way is simply to copy sagetex.sty into the same directory as your LaTeX document. Since the current directory is always searched when typesetting a document, this will always work.

There are a couple small problems with this, however: the first is that you will end up with many unnecessary copies of sagetex.sty scattered around your computer. The second and more serious problem is that if you upgrade Sage and get a new version of SageTeX, the Python code and LaTeX code for SageTeX may no longer match, causing errors.

• The second way is to use the TEXINPUTS environment variable. If you are using the bash shell, you can do

export TEXINPUTS="SAGE_ROOT/local/share/texmf//:"

where SAGE_ROOT is the location of your Sage installation. Note that the double slash and colon at the end of that line are important. Thereafter, TeX and friends will find the SageTeX style file. If you want to make this change permanent, you can add the above line to your .bashrc file. If you are using a different shell, you may have to modify the above command to make the environment variable known; see your shell’s documentation for how to do that.

One flaw with this method is that if you use applications like TeXShop, Kile, or Emacs/AucTeX, they will not necessarily pick up the environment variable, since when they run LaTeX, they may do so outside your usual shell environment.

If you ever move your Sage installation, or install a new version into a new directory, you’ll need to update the above command to reflect the new value of SAGE_ROOT.

• The third (and best) way to make TeX aware of sagetex.sty is to copy that file into a convenient place in your home directory. In most TeX distributions, the texmf directory in your home directory is automatically searched for packages. To find out exactly what this directory is, do the following on the command line:

kpsewhich -var-value=TEXMFHOME


which will print out a directory, such as /home/drake/texmf or /Users/drake/Library/texmf. Copy the tex/ directory from SAGE_ROOT/local/share/texmf/ into your home texmf directory with a command like

cp -R SAGE_ROOT/local/share/texmf/tex TEXMFHOME

where SAGE_ROOT is, as usual, replaced with the location of your Sage installation and TEXMFHOME is the result of the kpsewhich command above.

If you upgrade Sage and discover that SageTeX no longer works, you can simply repeat these steps and the Sage and TeX parts of SageTeX will again be synchronized.

• For installation on a multiuser system, you just modify the above instructions appropriately to copy sagetex.sty into a systemwide TeX directory. Instead of the directory TEXMFHOME, probably the best choice is to use the result of

kpsewhich -var-value=TEXMFLOCAL


which will likely produce something like /usr/local/share/texmf. Copy the tex directory as above into the TEXMFLOCAL directory. Now you need to update TeX’s database of packages, which you can do simply by running

texhash TEXMFLOCAL

as root, replacing TEXMFLOCAL appropriately. Now all users of your system will have access to the LaTeX package, and if they can also run Sage, they will be able to use SageTeX.

Warning

it’s very important that the file sagetex.sty that LaTeX uses when typesetting your document match the version of SageTeX that Sage is using. If you upgrade your Sage installation, you really should delete all the old versions of sagetex.sty floating around.

Because of this problem, we recommend copying the SageTeX files into your home directory’s texmf directory (the third method above). Then there is only one thing you need to do (copy a directory) when you upgrade Sage to insure that SageTeX will work properly.

## SageTeX documentation¶

While not strictly part of installation, it bears mentioning here that the documentation for SageTeX is maintained in SAGE_ROOT/local/share/doc/sagetex/sagetex.pdf. There is also an example file in the same directory – see example.tex and example.pdf, the pre-built result of typesetting that file with LaTeX and Sage. You can also get those files from the SageTeX bitbucket page.

## SageTeX and TeXLive¶

One potentially confusing issue is that the popular TeX distribution TeXLive 2009 includes SageTeX. This may seem nice, but with SageTeX, it’s important that the Sage bits and LaTeX bits be synchronized – which is a problem in this case, since both Sage and SageTeX are updated frequently, and TeXLive is not. While at the time of this writing (March 2013), many Linux distributions have moved on to more recent releases of TeXLive, the 2009 release lingers and is, in fact, the source of most bug reports about SageTeX!

Because of this, it is strongly recommended that you always install the LaTeX part of SageTeX from Sage, as described above. The instructions above will insure that both halves of SageTeX are compatible and will work properly. Using TeXLive to provide the LaTeX side of SageTeX is not supported.