[RFC] Add latex representation to DenseMatrix

[eendebakpt]

• Add a _repr_latex_ method to the DenseMatrix class.
• Add truncation for large matrices

Related to symengine/symengine#1701

[certik]

Nice!

I think in general these things should go into the C++ symengine, and we should just call it from the Python wrappers. That way any language will benefit and we only have to maintain this at one place.

Let me know what you think. I can help you get started in the C++ codebase if you are interested. Essentially this should go here: https://github.com/symengine/symengine/blob/88cf2e2ff482f64fae6c18ae93b8a30b6adef632/symengine/printers/latex.cpp. I don't know if we can simply add a method or figure out a way to handle matrices (I think they might be separate classes), but either way, I would do this in C++.

[eendebakpt]

Nice!

I think in general these things should go into the C++ symengine, and we should just call it from the Python wrappers. That way any language will benefit and we only have to maintain this at one place.

Let me know what you think. I can help you get started in the C++ codebase if you are interested.

If there would be other languages that benefit from latex it might indeed be good to move this into the symengine part. Otherwise it is probably easier to implement it on the python side.
I am comfortable with C++, but some pointers into the symengine structure would be helpful. In particular: I think the basic elements of a DenseMatrix are Basic objects. Where is the (latex) printing for the DenseMatrix and Basic objects? And which other structures to consider.

The latex printing of simple objects from the python side also seems not to be implemented, although a _repr_latex_ is present:

[isuruf]

The latex printing of simple objects from the python side also seems not to be implemented, although a repr_latex is present:

You need to do init_printing() to make it work,

[eendebakpt]

The latex printing of simple objects from the python side also seems not to be implemented, although a repr_latex is present:

You need to do init_printing() to make it work,

Thanks for the pointer. On my system it is not working:

Can be fixed by commenting out the lines

# To not expose internals
del lib.symengine_wrapper
del lib

from the symengine __init__.py. See #371.

@isuruf

[certik]

Try this in a jupyter notebook. The init_printing should work.

[certik]

@isuruf, since DenseMatrix is not part of the SymEngine visitor pattern, and currently does not have a latex printer, what do you think is the best design for printing latex? In symengine/printers.h we have std::string latex(const Basic &x); but that accepts Basic. I wonder if we can add another overload like latex(const DenseMatrix &x);, add an implementation into symengine/printers/latex.cpp and then just call it from the Python wrappers.

[isuruf]

In symengine/printers.h we have std::string latex(const Basic &x); but that accepts Basic. I wonder if we can add another overload like latex(const DenseMatrix &x);, add an implementation into symengine/printers/latex.cpp and then just call it from the Python wrappers.

Yes, that sounds good.

[eendebakpt]

@isuruf I updated this PR based on symengine/symengine#1847. Could you help me out with the cython part where the python object is mapped to a c++ symengine object?

[peendebak]

@isuruf Could you have a look at the cython part of the PR? With the c++ part merged, this is should be quite small.

[peendebak]

@isuruf The CI is failing because a python object cannot be assigned to the ctypes DenseMatrix. Could you have a look at it?

[isuruf]

Thanks