#6101: computation of induced morphism on homology and cohomology of simplicial
complex morphisms
-------------------------------------+-------------------------------------
Reporter: bantieau | Owner: bantieau
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-6.10
Component: algebraic | Resolution:
topology | Merged in:
Keywords: | Reviewers: Travis Scrimshaw
Authors: John Palmieri | Work issues:
Report Upstream: N/A | Commit:
Branch: | b6c565763a2df99471bb6b574f60d15450b44c2e
public/algtop/induced_maps-6101 | Stopgaps:
Dependencies: #19179, #6102, |
#18175 |
-------------------------------------+-------------------------------------
Changes (by {'newvalue': u'John Palmieri', 'oldvalue': ''}):
* cc: nthiery, SimonKing (added)
* commit: 953e0a6489a3eca48b13b1e91ece798c51a6fe5c =>
b6c565763a2df99471bb6b574f60d15450b44c2e
* reviewer: => Travis Scrimshaw
* branch: u/jhpalmieri/induced-maps => public/algtop/induced_maps-6101
* author: => John Palmieri
Comment:
Man...non hashable parents really throw a big wrench into the coercion
framework. In some ways that is not surprising, as they get put into a big
`dict` to store the necessary coercions, but I would have liked it to
better handle non-hashable parents.
Well, one of the problems that you had was `Element` tries to use coercion
on elements which do not define rich comparisons, which caused problems
until I changed `Simplex.__cmp__` to rich comparisons (I <3
`functools.total_ordering`). However, even with that change, I could not
get the combination of `class Element(Simplex, Element)` in
`SimplicialComplex` to pickle (granted, I did not try too hard). I think
the problem is that `SimplicialComplex` is defined by a set of its
elements, and we get a loop of sorts with the pickling...
Therefore I decided to just add a warning message to `SimplicialComplex`
instead. Simon, Nicolas, the reason I am cc-ing you is to make sure that
this abuse of `Parent` is acceptable to you (or if you had any thoughts
about the pickling issues). At least until a follow-up ticket takes care
of things.
----
New commits:
||[http://git.sagemath.org/sage.git/commit/?id=b6c565763a2df99471bb6b574f60d15450b44c2e
b6c5657]||{{{Add a warning about the abuse of Parent in simplicial
complex.}}}||
--
Ticket URL: <http://trac.sagemath.org/ticket/6101#comment:38>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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