Opened 3 years ago
Last modified 3 years ago
#24900 needs_work defect
Tensor product and coefficients
Reported by: | hivert | Owned by: | |
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Priority: | major | Milestone: | sage-8.2 |
Component: | linear algebra | Keywords: | tensor product, free modules |
Cc: | nthiery, tscrim | Merged in: | |
Authors: | Florent Hivert | Reviewers: | |
Report Upstream: | N/A | Work issues: | |
Branch: | u/hivert/tensor_product_and_coefficients (Commits, GitHub, GitLab) | Commit: | 009c70a07140b6df68ac61ccd38db52c0b1188b1 |
Dependencies: | Stopgaps: |
Description
Tensor products of combinatorial free modules still use an old version of cartesian product. As a consequence extracting a coefficient is not possible:
sage: F = CombinatorialFreeModule(ZZ, [1,2]); F.__custom_name = "F" sage: G = CombinatorialFreeModule(ZZ, [3,4]); G.__custom_name = "G" sage: T = tensor([F, G]); T sage: T.basis()[(1,3)].coefficient((1,3)) ... NotImplementedError:
I fix that. As a side effect, this change the result of an_element
so that I
have to fix a few doctests.
Moreover, building the tensor of two infinite dimensional FM now raises a correct warning:
sage: F = CombinatorialFreeModule(ZZ, NN) sage: T = tensor([F, F]); T Free module generated by Non negative integer semiring over Integer Ring ⊗ Free module generated by Non negative integer semiring over Integer Ring sage: T.an_element() /home/data/Sage-Install/sage-dev/local/lib/python2.7/site-packages/sage/categories/sets_cat.py:2159: UserWarning: Sage is not able to determine whether the factors of this Cartesian product are finite. The lexicographic ordering might not go through all elements. warn("Sage is not able to determine whether the factors of " 2*B[0] ⊗ B[1] + B[0] ⊗ B[0] + 3*B[0] ⊗ B[2] + B[42] ⊗ B[42]
I'm hiding this by asking only finite dim FM.
Change History (5)
comment:1 Changed 3 years ago by
- Branch set to u/hivert/tensor_product_and_coefficients
comment:2 Changed 3 years ago by
- Commit set to 009c70a07140b6df68ac61ccd38db52c0b1188b1
- Status changed from new to needs_review
comment:3 Changed 3 years ago by
many failing doctests
comment:4 Changed 3 years ago by
- Status changed from needs_review to needs_work
comment:5 Changed 3 years ago by
- Cc tscrim added
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New commits:
Fix tensor prod. using old cartesian prod.