#12693: bug in jordan_form(transformation=true) for integer matrices
------------------------------+---------------------------------------------
Reporter: hthomas | Owner: jason, was
Type: defect | Status: new
Priority: major | Milestone: sage-5.0
Component: linear algebra | Keywords: jordan form
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
Stopgaps: |
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Comment(by dsm):
Looks like a simple type error somewhere. Fails for integers, works for
rationals:
{{{
sage: M
[ 2 2 2]
[ 0 0 0]
[-2 -2 -2]
sage: parent(M)
Full MatrixSpace of 3 by 3 dense matrices over Integer Ring
sage: M.jordan_form(transformation=True)
(
[0 1|0]
[0 0|0] [ 2 1 1]
[---+-] [ 0 0 0]
[0 0|0], [-2 0 -1]
)
}}}
but
{{{
sage: (M/1).jordan_form(transformation=True)
(
[0 1|0]
[0 0|0] [ 2 1 0]
[---+-] [ 0 0 1]
[0 0|0], [-2 0 -1]
)
sage: parent(M/1)
Full MatrixSpace of 3 by 3 dense matrices over Rational Field
sage: (M/1).jordan_form(transformation=True)
(
[0 1|0]
[0 0|0] [ 2 1 0]
[---+-] [ 0 0 1]
[0 0|0], [-2 0 -1]
)
sage: J, P = (M/1).jordan_form(transformation=True)
sage: J == P**(-1)*M*P
True
}}}
Will see if I can track it down.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12693#comment:1>
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