#6814 closed defect (invalid)
jordan_form transformation lack of precision sage 4.1.1
Reported by: | Henryk.Trappmann | Owned by: | tbd |
---|---|---|---|
Priority: | major | Milestone: | sage-duplicate/invalid/wontfix |
Component: | linear algebra | Keywords: | jordan, precision, matrix, transformation |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
There is an example for a lack of precision exception in the doc of jordan_form
sage: b = matrix(ZZ,3,3,range(9)) sage: jf, p = b.jordan_form(RealField(15), transformation=True) ... ValueError: cannot compute the transformation matrix due to lack of precision
But if one increases the precision to the maximum still the same error occurs
sage: b = matrix(ZZ,3,3,range(9)) sage: jf, p = b.jordan_form(RealField(16777216), transformation=True) ... ValueError: cannot compute the transformation matrix due to lack of precision
Change History (3)
comment:1 Changed 10 years ago by
- Component changed from algebra to linear algebra
comment:2 Changed 10 years ago by
- Report Upstream set to N/A
- Resolution set to invalid
- Status changed from new to closed
comment:3 Changed 10 years ago by
- Milestone changed from sage-4.3.1 to sage-duplicate/invalid/wontfix
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The error messages come up because the code does not actually detect numerically instability. Instead, it notices when it fails, and assumes the only possible reason for this could be numerical instability. Instead, there's a bug in the actual code.
Thus, this ticket can be closed as being "invalid".