Prepare Polyhedra parent factory to handle more general ambient spaces

[mkoeppe]

This adds a new way to set up a Polyhedra parent.

        sage: V = VectorSpace(QQ, 3)
        sage: Polyhedra(V) is Polyhedra(QQ, 3)
        True

Part of #30198.

[mkoeppe]

New commits:

​20082d5

sage.geometry.polyhedron.parent.Polyhedra: Generalize the factory

[gh-kliem]

sage: V = FiniteRankFreeModule(QQ, 2)
sage: Polyhedra(V)
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/home/jonathan/Applications/sage/local/lib/python3.7/site-packages/sage/structure/category_object.pyx in sage.structure.category_object.CategoryObject.getattr_from_category (build/cythonized/sage/structure/category_object.c:6954)()
    837         try:
--> 838             return self.__cached_methods[name]
    839         except KeyError:

KeyError: 'dimension'

During handling of the above exception, another exception occurred:

AttributeError                            Traceback (most recent call last)
<ipython-input-30-0c140d68c4dd> in <module>()
----> 1 Polyhedra(V)

/home/jonathan/Applications/sage/local/lib/python3.7/site-packages/sage/geometry/polyhedron/parent.py in Polyhedra(ambient_space_or_base_ring, ambient_dim, backend, ambient_space, base_ring)
    113             base_ring = ambient_space.base_ring()
    114         if ambient_dim is None:
--> 115             ambient_dim = ambient_space.dimension()
    116         if ambient_space is not FreeModule(base_ring, ambient_dim):
    117             raise NotImplementedError('ambient_space must be standard free module')

/home/jonathan/Applications/sage/local/lib/python3.7/site-packages/sage/structure/category_object.pyx in sage.structure.category_object.CategoryObject.__getattr__ (build/cythonized/sage/structure/category_object.c:6876)()
    830             AttributeError: 'PrimeNumbers_with_category' object has no attribute 'sadfasdf'
    831         """
--> 832         return self.getattr_from_category(name)
    833 
    834     cdef getattr_from_category(self, name):

/home/jonathan/Applications/sage/local/lib/python3.7/site-packages/sage/structure/category_object.pyx in sage.structure.category_object.CategoryObject.getattr_from_category (build/cythonized/sage/structure/category_object.c:7039)()
    845                 cls = self._category.parent_class
    846 
--> 847             attr = getattr_from_other_class(self, cls, name)
    848             self.__cached_methods[name] = attr
    849             return attr

/home/jonathan/Applications/sage/local/lib/python3.7/site-packages/sage/cpython/getattr.pyx in sage.cpython.getattr.getattr_from_other_class (build/cythonized/sage/cpython/getattr.c:2548)()
    387         dummy_error_message.cls = type(self)
    388         dummy_error_message.name = name
--> 389         raise AttributeError(dummy_error_message)
    390     cdef PyObject* attr = instance_getattr(cls, name)
    391     if attr is NULL:

AttributeError: 'FiniteRankFreeModule_with_category' object has no attribute 'dimension'

I think we should add dimension as an alias for rank in FiniteRankFreeModule.

[mkoeppe]

Thanks for catching this. I'm working on an improvement and will add some more tests as well.

Let's not do changes to the modules API on this ticket.

[mkoeppe]

Replying to mkoeppe:

Let's not do changes to the modules API on this ticket.

I've created #30215 for dimension.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​ab7c5ff

Polyhedra: Handle ambient_space = a free module correctly

[gh-kliem]

For CombinatorialFreeModule and FiniteRankFreeModule I'm getting both NotImplementedError: ambient_space must be a standard free module.

I assume that #30094 takes care of this?

If this is the case, you can put this on positive review on my behalf.

[mkoeppe]

That's right. Based on #30094 and the present ticket, the functionality will be implemented in #30198.

Thanks!