#15303: Coercion discovery fails to be transitive
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Reporter: nbruin | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-5.13
Component: coercion | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/SimonKing/ticket/15303 | dcd8d68fb30f752bcd595d73fe2d3925e7db671f
Dependencies: #14711 | Stopgaps:
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Changes (by nbruin):
* commit: => dcd8d68fb30f752bcd595d73fe2d3925e7db671f
Comment:
Replying to [comment:9 SimonKing]:
> PS: We also have `convert_from_list`, and I guess we should proceed
similarly for `coerce_from_list`.
yes, conversion probably needs some attention too. However, since
conversions exits between a lot more pairs of parents, Do we use
backtracking to discover them? There are almost certainly loops:
trivially, because ZZ->Z/nZ and Z/nZ->ZZ are valid conversions.
If we want a memory leak-free implementation I suspect having conversion
without lifetime implications in either direction is required. Definitely
material for another ticket.
----
Last 10 new commits:
||[changeset:dcd8d68]||Use registered embeddings for backtracking in the
coercion model||
||[changeset:85cf7e8]||Merge branch 'ticket/14711' into ticket/15303||
||[changeset:364b985]||Add warning to string repr of weakened maps.
Implement copying for *all* kinds of maps.||
||[changeset:5168cfd]||Generic copy method for maps, using _update_slots
Use a cdef _codomain, since the codomain is strongly refed anyway Add
doctests||
||[changeset:452d216]||Add docs to SchemeMorphism||
||[changeset:05fb569]||Change SchemeMorphism back (to cope with a Cython
bug), copying the new code from sage.categories.map.Map||
||[changeset:8fd09d5]||Copying of PolynomialBaseringInjection and
FormalCompositeMap||
||[changeset:be37145]||Let SchemeMorphism inherit from Morphism, not from
Element||
||[changeset:0f38a2c]||Keep strong reference to codomain of weakened
coerce maps Keep strong reference to domains of *registered* coercions||
||[changeset:a53261d]||Keep a strong reference to the codomain of
PrecomposedAction||
--
Ticket URL: <http://trac.sagemath.org/ticket/15303#comment:12>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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