#3163 closed defect (duplicate)
Problems with echelon_form over ComplexField
Reported by: | dunfield | Owned by: | was |
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Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | linear algebra | Keywords: | |
Cc: | mhansen | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | Work issues: | ||
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
For certain well-conditioned floating-point matrices with entries in ComplexField?, echelon_form can return matrices which are not in (approximate) echelon_form. This breaks methods like rank(), right_solve() and inverse(). I've attached a sample matrix which illustrates this
sage: A = load("./prob-sol.sobj") sage: A.parent() Full MatrixSpace of 5 by 5 dense matrices over Complex Field with 1010 bits of precision sage: matrix(CDF, A.echelon_form()) [ 1.0 0 -3.5*I 0 -20.0 + 12.0*I] [ 0 1.0 1.0 0 -4.0 + 1.0*I] [ 0 0 1.0 + 4.55695126222e-305*I 0 -2.33592727654 + 0.497614402099*I] [ 0 0 -4.0 1.0 -2.0] [ 0 0 -2.0 0 0] sage: CC(A.det()) 76.1312551138321 - 5.28799080668534*I sage: A.rank() 4
This bug is probably related to #2256 and #1132 but there the problem with echelon_form is more subtle (1 entries on the diagonal which aren't quite 1), which is why I opened this new ticket.
Change History (2)
comment:1 Changed 8 years ago by dunfield
- Resolution set to duplicate
- Status changed from new to closed
comment:2 Changed 8 years ago by mabshoff
- Milestone changed from sage-3.0.2 to sage-duplicate/invalid
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