LaTeX equations do not render in google Colaboratory when using matplotlib

问题

If I take the official example containing latex from the matplotlib website:

from matplotlib import rc
rc('font',**{'family':'sans-serif','sans-serif':['Helvetica']})
rc('text', usetex=True)
import numpy as np
import matplotlib.pyplot as plt


# Example data
t = np.arange(0.0, 1.0 + 0.01, 0.01)
s = np.cos(4 * np.pi * t) + 2

plt.rc('text', usetex=True)
plt.rc('font', family='serif')
plt.plot(t, s)

plt.xlabel(r'\textbf{time} (s)')
plt.ylabel(r'\textit{voltage} (mV)',fontsize=16)
plt.title(r"\TeX\ is Number "
          r"$\displaystyle\sum_{n=1}^\infty\frac{-e^{i\pi}}{2^n}$!",
          fontsize=16, color='gray')
# Make room for the ridiculously large title.
plt.subplots_adjust(top=0.8)

plt.savefig('tex_demo')
plt.show()

and try to run it in a Google Colab notebook it will produce a big stacktrace with the following message at the end:

 [Errno 2] No such file or directory: 'latex': 'latex'

Why does this happen and how can I fix that?

My attempts:
I thought this error might happen because latex is missing in the serving VM so I tried to install texlive before importing matplotlib with:

! sudo apt-get install texlive-latex-recommended

This finishes successfully. However matplotlib complains about some missing latex *.sty file which after googling should be contained in the texlive-latex-extra package. But during the installation of the extra package some errors occurred:

Err:5 http://security.ubuntu.com/ubuntu bionic-updates/main amd64 ruby2.5 amd64 2.5.1-1ubuntu1.1
  404  Not Found [IP: 91.189.88.162 80]
Get:16 http://archive.ubuntu.com/ubuntu bionic/universe amd64 texlive-latex-extra all 2017.20180305-2 [10.6 MB]
Err:13 http://security.ubuntu.com/ubuntu bionic-updates/main amd64 libruby2.5 amd64 2.5.1-1ubuntu1.1
  404  Not Found [IP: 91.189.88.162 80]
Get:17 http://archive.ubuntu.com/ubuntu bionic/universe amd64 texlive-plain-generic all 2017.20180305-2 [23.6 MB]
Fetched 41.5 MB in 4s (11.3 MB/s)

So I cant finish the installation of texlive-latex-extra. How can I proceed?

回答1:

So this a very hacky solution, but I got it to work atleast. The problem was indeed the missing texlive package. After installing texlive-latex-recommended one still needs a type1cm.sty file for the matplotlib example to work. Since the extra package could not be installed easily, I manually installed the type1cm package. To achieve this I executed following commands before importing matplotlib:

! sudo apt-get install texlive-latex-recommended #1
! sudo apt-get install dvipng texlive-fonts-recommended #2
! wget http://mirrors.ctan.org/macros/latex/contrib/type1cm.zip #3
! unzip type1cm.zip -d /tmp/type1cm #4
! cd /tmp/type1cm/type1cm/ && sudo latex type1cm.ins  #5
! sudo mkdir /usr/share/texmf/tex/latex/type1cm #6
! sudo cp /tmp/type1cm/type1cm/type1cm.sty /usr/share/texmf/tex/latex/type1cm #7
! sudo texhash #8

Those commands will do the following:

minimal texlive installation which still works
not sure if those packages are necessary, but wont hurt to much
download type1cm package from ctan offically
unzip to /tmp/type1cm
install package by running latex command on type1cm.ins file. Note that providing the path directly to the latex command didnt work. Also the cd and latex command have to be executed in the same line( behind the the same ! symbol), otherwise the cd has no effect
create folder for type1cm packge in texmf tree
copy .sty file there
update tex so that it find the new package

Resources:
How to install type1cm
Where to place *.sty files in Linux texlive install

来源：https://stackoverflow.com/questions/55746749/latex-equations-do-not-render-in-google-colaboratory-when-using-matplotlib

标签

python

matplotlib

latex

google-colaboratory