Opened 5 months ago
Closed 4 months ago
#21760 closed defect (fixed)
Fix tensor products for some chain complexes
Reported by: | jhpalmieri | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-7.5 |
Component: | algebraic topology | Keywords: | |
Cc: | tscrim | Merged in: | |
Authors: | Travis Scrimshaw | Reviewers: | Frédéric Chapoton |
Report Upstream: | N/A | Work issues: | |
Branch: | 3b86bf3 (Commits) | Commit: | 3b86bf3c19f38097304933da9e08420ddfb8c732 |
Dependencies: | Stopgaps: |
Description
When tensoring chain complexes, tensor products of two 0 x n
matrices don't work correctly:
sage: C = ChainComplex({0: matrix(ZZ, 0, 1)}, degree=-1) sage: ascii_art(C) 0 <-- C_0 <-- 0 sage: C.homology() {0: Z} sage: C.tensor(C) Trivial chain complex over Integer Ring sage: C.tensor(C).homology() {}
Change History (4)
comment:1 Changed 4 months ago by
- Branch set to public/homology/fix_tensor_product_chain_complexes-21760
- Commit set to 3b86bf3c19f38097304933da9e08420ddfb8c732
- Status changed from new to needs_review
comment:2 Changed 4 months ago by
- Reviewers set to Frédéric Chapoton
- Status changed from needs_review to positive_review
ok, let it be
comment:3 Changed 4 months ago by
Thank you for the fix and the review.
comment:4 Changed 4 months ago by
- Branch changed from public/homology/fix_tensor_product_chain_complexes-21760 to 3b86bf3c19f38097304933da9e08420ddfb8c732
- Resolution set to fixed
- Status changed from positive_review to closed
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So, I should not try to optimize if it is a
0 x n
differential matrix; those still carry useful information.New commits:
Premature optimization is the root of not handling 0 x n matrices.