Opened 2 years ago
Last modified 5 months ago
#30263 new defect
declare_union yields wrong results — at Version 4
Reported by: | gh-mjungmath | Owned by: | |
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Priority: | major | Milestone: | sage-9.7 |
Component: | manifolds | Keywords: | sets, union |
Cc: | egourgoulhon, tscrim | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | #31680 | Stopgaps: |
Description (last modified by )
sage: M = Manifold(3, 'M') sage: U = M.open_subset('U'); V = M.open_subset('V'); W = M.open_subset('W') sage: M.declare_union(U, V, W) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-3-c7f527dcc1ea> in <module>() ----> 1 M.declare_union(U, V, W) TypeError: declare_union() takes 3 positional arguments but 4 were given sage: def label(element): ....: try: ....: return element._name ....: except AttributeError: ....: return '[' + ', '.join(sorted(x._name for x in element)) + ']' sage: P = M.subset_poset(open_covers=True); P.plot(element_labels={element: label(element) for element in P}) sage: M.declare_union(U, V.union(W)) sage: P = M.subset_poset(open_covers=True); P.plot(element_labels={element: label(element) for element in P}) sage: U.union(V).union(W) Open subset U_union_V_union_W of the 3-dimensional differentiable manifold M sage: P = M.subset_poset(open_covers=True); P.plot(element_labels={element: label(element) for element in P}) sage: U.union(V.union(W)) 3-dimensional differentiable manifold M sage: P = M.subset_poset(open_covers=True); P.plot(element_labels={element: label(element) for element in P}) # same
I propose to allow more than two arguments for declare_union
. Furthermore, something went wrong with the commutativity of the union. This should be investigated, too.
Change History (4)
comment:1 Changed 22 months ago by
- Milestone changed from sage-9.2 to sage-9.3
comment:2 Changed 16 months ago by
- Milestone changed from sage-9.3 to sage-9.4
comment:3 Changed 16 months ago by
Unions of several subsets also appear in another form - as open covers (which are merely lists of subsets and not manifold subsets in their own right). One might ask whether this could be unified as well.
comment:4 Changed 16 months ago by
- Dependencies set to #31680
- Description modified (diff)
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Sage development has entered the release candidate phase for 9.3. Setting a new milestone for this ticket based on a cursory review.