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substitute not working with SymPy

See original GitHub issue

Calling sorted( ) in https://github.com/HPAC/matchpy/blob/5cae3f275e3a1f725518516bf3c700dc3be03a56/matchpy/functions.py#L87 fails with SymPy, as SymPy objects are not comparable with operators (<, <=, >, >=). Operators are overloaded in SymPy to create instances of inequality objects.

SymPy has a function called default_sort_key meant to deal with this problem:

from sympy import symbols
x, y, z = symbols("x y z")
from sympy.core.compatibility import default_sort_key
sorted([z, x, y], key=default_sort_key)

The question is, is it possible to modify MatchPy to specify a custom sorting key so that SymPy can specify the way its objects should be sorted?

Or is it an issue with Multiset?

Issue Analytics

State:
Created 3 years ago
Comments:11 (10 by maintainers)

Top GitHub Comments

1reaction

Upabjojrcommented, Dec 30, 2020

I guess it would also make sense to add tests for the SymPy compatibility before the next release. Are you working on those tests?

We have these tests in SymPy. I have merged some extensions to sympy.utilities.matchpy_connector 15 days ago. We may need to wait for a new release of SymPy before we can add tests to MatchPy.

0reactions

hbarthelscommented, Dec 30, 2020

Is it important to you that we create a new release of MatchPy as soon as possible? If not, I would prefer to wait a bit in case more problems show up. I guess it would also make sense to add tests for the SymPy compatibility before the next release. Are you working on those tests?

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