Opened 13 years ago
Closed 12 years ago
#7458 closed enhancement (fixed)
Sylvester matrix for polynomials
Reported by: | carlohamalainen | Owned by: | malb |
---|---|---|---|
Priority: | minor | Milestone: | sage-4.6.2 |
Component: | commutative algebra | Keywords: | Sylvester matrix |
Cc: | Merged in: | sage-4.6.2.alpha3 | |
Authors: | Carlo Hamalainen, Luis Felipe Tabera Alonso | Reviewers: | David Loeffler |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Small patch to add Sylvester matrix calculation for univariate and multivariate polynomials.
I think that my patch is a bit more general (and has doctests) compared to didier deshommes' patch here, which seems to have never been merged:
http://sage.math.washington.edu/home/dfdeshom/custom/patches/sylveste...
Attachments (3)
Change History (10)
Changed 13 years ago by
Changed 12 years ago by
comment:1 Changed 12 years ago by
- Keywords Sylvester matrix added
- Report Upstream set to N/A
- Status changed from new to needs_work
comment:2 Changed 12 years ago by
- I have added more documentation and doctest.
- The variable argument is now optional in both univariate and multivariate. If it is not used, the first variable of the polynomial ring is used.
- I have added coercion to be able to compute the Sylvester matrix of polynomials in different rings, for ex. ZZ[x] and QQ[x]
- solved an issue for the dimension of the matrix of the sylvester matrix of (xn, 0)
It is not ready for review because the sylvester matrix of (0,0) is not implemented.
Changed 12 years ago by
comment:3 Changed 12 years ago by
- Status changed from needs_work to needs_review
Finally, if one of the polynomials is zero, the code raises a ValueError?.
comment:4 Changed 12 years ago by
Apply trac-7458-sylvester-rebase-4.6.patch, trac-7458-sylvester-improvements.patch
comment:5 Changed 12 years ago by
- Reviewers set to David Loeffler
- Status changed from needs_review to positive_review
Very nice. I am impressed with the thoroughness of the testing of corner cases here. All doctests in sage/rings pass, and the reference manual builds OK.
comment:6 Changed 12 years ago by
- Milestone changed from sage-4.6.1 to sage-4.6.2
- Summary changed from [with patch, needs review] Sylvester matrix for polynomials to Sylvester matrix for polynomials
comment:7 Changed 12 years ago by
- Merged in set to sage-4.6.2.alpha3
- Resolution set to fixed
- Status changed from positive_review to closed
This is a very basic feature that has to be in Sage.
I have rebased Carlo patch to 4.6 but have not touched the code.
I have some concerns that makes me mark the patch as needs work:
In particular, I am not sure how to deal with the sylvester matrix of 0 and constant or 0 and 0 Curretly it throws an error. My opinion is that this is not defined but should throw a more meaningful error.
Maple for instance return the empty matrix. So in maple:
Determinant(Sylvester_Matrix) != Resultant
In this corner cases.
I will try to check what other CAS do to get a wider picture.