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asked 2017-09-18 03:15:57 -0500

matpen gravatar image

I wrote a C++ library and the related python bindings, and I would like to make use of them from sage. But whatever I try, I cannot get sage to load the library. Here is what I tried:


export SAGE_PATH="$SAGE_PATH:/opt/mylib/bindings"
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/opt/mylib/lib::/opt/mylib/dependencies"

However, when I try to import from a jupyter notebook:

import mylib.mymodule.mysubmodule

I get the error:

ImportError: /usr/lib/ undefined symbol: sgemv_thread_n

I only could find one reference (ticket 22006 on - sorry, cannot post links yet) to a similar problem, however without resolution (the suggested workaround, namely to install libopenblas-dev did not work for me). Note that mylib does not depend in any way on BLAS.


export SAGE_PATH="$SAGE_PATH:/opt/mylib/bindings"
echo -e "/opt/mylib/lib\n/opt/mylib/dependencies" > /etc/
sudo ldconfig

But the library cannot be found this way:

ImportError: cannot open shared object file: No such file or directory


export SAGE_PATH="$SAGE_PATH:/opt/mylib/bindings"
sudo ln -s /opt/mylib/lib/ /usr/lib/sagemath/local/lib/
sudo ln -s /opt/mylib/lib/ /usr/local/lib/

This results in the same import error as in SECOND ATTEMPT.


export SAGE_PATH="$SAGE_PATH:/opt/mylib/bindings"
sudo ln -s /opt/mylib/lib/ /lib/

Now the library finally got loaded, but it cannot find its dependencies.

ImportError: cannot open shared object file: No such file or directory


What is the proper way to make sage resolve a custom library and its dependencies? I understand that sage tries to isolate itself as much as possible from the system, and I have also read that there is some "magic" going on to adjust environment variables: this seems to cause the problem (1).


Working on Ubuntu 16.04 LTS with sage installed from ppa as follows:

apt-add-repository -y ppa:aims/sagemath
apt-get update
apt install sagemath-upstream-binary

Note that everything works as expected when using the library from the system python console.

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What about the following scenario? (Written only with the hope of isolating the problem point.)

  • starting a terminal, typing in it

    sage -sh

    to start the sage shell, which sets all environment variables as needed, then

  • extending / setting the needed variables SAGE_PATH, and LD_LIBRARY_PATH as in one of the attempts,

  • starting sage in this terminal and testing

  • and / or starting jupyter from this terminal and testing.

dan_fulea gravatar imagedan_fulea ( 2017-09-18 14:25:11 -0500 )edit

@dan_fuela thank you, just tried, but that leads to the same results (either library not found, or libblas conflict)

matpen gravatar imagematpen ( 2017-09-18 15:31:22 -0500 )edit

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answered 2017-09-29 05:45:44 -0500

Jeroen Demeyer gravatar image

I think the easiest solution is to install your library and bindings inside the Sage environment instead of in /opt/mylib. Run

sage --sh

which will drop you in a "Sage shell". Now, install your stuff in $SAGE_LOCAL. For an autotools project, this would be

./configure --prefix="$SAGE_LOCAL" && make && make install

For a Python project, plain pip will work:

pip install PKGNAME
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Asked: 2017-09-18 03:15:57 -0500

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Last updated: Sep 29