Opened 8 years ago
Closed 8 years ago
#17859 closed defect (fixed)
Use coercion instead of pushout in matrix actions
Reported by: | vdelecroix | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-6.6 |
Component: | coercion | Keywords: | |
Cc: | Merged in: | ||
Authors: | Jeroen Demeyer | Reviewers: | Travis Scrimshaw |
Report Upstream: | N/A | Work issues: | |
Branch: | 9da3db6 (Commits, GitHub, GitLab) | Commit: | 9da3db64750114e4c230a83e96e2ab6544c3e104 |
Dependencies: | Stopgaps: |
Description (last modified by )
There is no coercion between QQ and finite rings
sage: cm = get_coercion_model() sage: cm.get_action(Zmod(2), QQ, operator.mul) is None True
This is right.
But we do have an action of matrices on vectors
sage: M = MatrixSpace(Zmod(2),2) sage: V = VectorSpace(QQ,2) sage: cm.get_action(M,V,operator.mul) Left action by Full MatrixSpace of 2 by 2 dense matrices over Ring of integers modulo 2 on Vector space of dimension 2 over Rational Field
or
sage: M = MatrixSpace(QQ,2) sage: V = VectorSpace(Zmod(2),2) sage: cm.get_action(M,V,operator.mul) Left action by Full MatrixSpace of 2 by 2 dense matrices over Rational Field on Vector space of dimension 2 over Ring of integers modulo 2
And this is wrong!
see also: #12865
Change History (9)
comment:1 Changed 8 years ago by
Description: | modified (diff) |
---|
comment:2 Changed 8 years ago by
Summary: | Wrong coercion between QQ and finite rings → Remove action of Z/nZ matrices on QQ vectors |
---|
comment:3 Changed 8 years ago by
Summary: | Remove action of Z/nZ matrices on QQ vectors → Use coercion instead of pushout in matrix actions |
---|
comment:4 Changed 8 years ago by
Authors: | → Jeroen Demeyer |
---|
comment:5 Changed 8 years ago by
Branch: | → u/jdemeyer/use_coercion_instead_of_pushout_in_matrix_actions |
---|---|
Commit: | → 437c4e8e481084a2b6414ce2878e2ae12cb98160 |
Status: | new → needs_review |
comment:6 Changed 8 years ago by
Reviewers: | → Travis Scrimshaw |
---|
LGTM, but could you add a linebreak to the doctest you added? Thanks.
comment:7 Changed 8 years ago by
Commit: | 437c4e8e481084a2b6414ce2878e2ae12cb98160 → 9da3db64750114e4c230a83e96e2ab6544c3e104 |
---|
Branch pushed to git repo; I updated commit sha1. New commits:
9da3db6 | Add line breaks in long doctest
|
comment:8 Changed 8 years ago by
Status: | needs_review → positive_review |
---|
comment:9 Changed 8 years ago by
Branch: | u/jdemeyer/use_coercion_instead_of_pushout_in_matrix_actions → 9da3db64750114e4c230a83e96e2ab6544c3e104 |
---|---|
Resolution: | → fixed |
Status: | positive_review → closed |
Note: See
TracTickets for help on using
tickets.
New commits:
Use coercion instead of pushout for matrix actions