Use CombinatorialPolyhedron to obtain faces of polyhedra

[gh-kliem]

We use CombinatorialPolyhedron to obtain the faces of fixed dimensions of a polyhedron.

We add a method face_generator, which iterates over all faces (possibly of fixed dimension).

With this ticket we can obtain the faces much faster and without generating the entire face lattice. The iterator is a true iterator in the sense that it has almost constant memory usage and does and no point store a list of all faces.

This ticket changes the order of the output of faces.

There is a conflict with #17215, as it assumes the faces in the old order. However, if this here looks good, #17215 can also be marked dependent on #28646.

[gh-kliem]

I accidentally pulled #28625 instead of #28621. As #28625 is closed, I don't feel like fixing the branch.

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New commits:

​b89610e	added combinatorial polyhedron as an attribute for polyhedra
​dfbe2ad	Merge branch 'public/28607' of git://trac.sagemath.org/sage into public/28621
​ed5518b	used CombinatorialPolyhedron to compute f_vector
​9bdd005	give an error message for polytopes in some cases; removed incorrect example
​acd671d	now we get a precice error message for inexact truncated dodecahedron
​bf85a62	subsequent calls for f_vector fail if first attempt fails
​36ac386	Merge branch 'public/28625' of git://trac.sagemath.org/sage into face_iter
​ca54051	polyhedron uses CombinatorialPolyhedron for :meth:`faces`; added :meth:`face_generator`

[git]

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

​6828a75

avoid import of PolyhedronFace; use existing method

[jipilab]

I would vote to change face_dimension to simply dimension.

The INPUT of combinatorial_face_to_polyhedral_face is too verbose to me.

A Polyhedron, the polyhedron containing the face A CombinatorialFace

OUTPUT:

A PolyhedronFace

is sufficient. If you insist to have the links on the documentation ok... But I would not be too verbose here.

[git]

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

​d85f055

simplified input/output

[gh-kliem]

Replying to jipilab:

I would vote to change face_dimension to simply dimension.

This is to be consistent with the method faces`.

[gh-kliem]

There will be a conflict with #17215.

[gh-kliem]

Rebased

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New commits:

​d9cb649

polyhedron uses CombinatorialPolyhedron for :meth:`faces`; added :meth:`face_generator`

[git]

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

​849e09a

fixed a new failing test

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​a4c3025	polyhedron uses CombinatorialPolyhedron for :meth:`faces`; added :meth:`face_generator`
​5f284dd	avoid import of PolyhedronFace; use existing method
​d15170d	simplified input/output
​4d53c14	fixed a new failing test