#12208: LU decomposition gives wrong results on cyclotomic matrices (MacOSX-
specific)
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Reporter: dimpase | Owner: jason, was
Type: defect | Status: new
Priority: major | Milestone: sage-4.8
Component: linear algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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Comment(by dimpase):
Replying to [comment:7 rbeezer]:
> Replying to [comment:6 rbeezer]:
> > Or maybe there is a better function to be using for the "magnitude" of
an element of an arbitrary ring/field? Maybe a question for sage-devel -
I can't think of the answer.
>
> Answering my own question. Maybe the {{{norm()}}} function (or method)
is a better choice. For a negative rational, it returns the negative
value, which I find odd (but maybe appropriate?).
>
> With test patch, I only get one doctest failure (a permutation matrix
changes) and the original example still gives the same {{{U}}} matrix.
>
> Dima - would you like to try out the test patch (built on 4.8.alpha3)?
I'm not sure yet it is the best solution, but it could be.
yes, this fixes the problem.
Dima
>
> Rob
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12208#comment:8>
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