id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
24900,Tensor product and coefficients,hivert,,"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.
",defect,needs_work,major,sage-8.2,linear algebra,,"tensor product, free modules",nthiery tscrim,,Florent Hivert,,N/A,,u/hivert/tensor_product_and_coefficients,009c70a07140b6df68ac61ccd38db52c0b1188b1,,