#12280: Incorrect saturation of integer matrix
------------------------------+---------------------------------------------
Reporter: vbraun | Owner: jason, was
Type: defect | Status: new
Priority: major | Milestone: sage-4.8
Component: linear algebra | Keywords: hnf echelon_form
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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Changes (by vbraun):
* keywords: saturation => hnf echelon_form
Comment:
75 is the cutoff where the hnf computation switches from
``algorithm='pari'`` to `algorithm='padic'``. The latter does not always
chop off zero rows:
{{{
sage: m = matrix([(-2, 1, 9, 2, -8, 1, -3, -1, -4, -1),
... (5, -2, 0, 1, 0, 4, -1, 1, -2, 0),
... (-11, 3, 1, 0, -3, -2, -1, -11, 2, -2),
... (-1, 1, -1, -2, 1, -1, -1, -1, -1, 7),
... (-2, -1, -1, 1, 1, -2, 1, 0, 2, -4)]).stack(
... 200 * identity_matrix(ZZ, 10))
sage: matrix(ZZ,m).hermite_form(algorithm='padic',
include_zero_rows=False)
[ 1 0 2 0 13 5 1 166 72 69]
[ 0 1 1 0 20 4 15 195 65 190]
[ 0 0 4 0 24 5 23 22 51 123]
[ 0 0 0 1 23 7 20 105 60 151]
[ 0 0 0 0 40 4 0 80 36 68]
[ 0 0 0 0 0 10 0 100 190 170]
[ 0 0 0 0 0 0 25 0 100 150]
[ 0 0 0 0 0 0 0 200 0 0]
[ 0 0 0 0 0 0 0 0 200 0]
[ 0 0 0 0 0 0 0 0 0 200]
[ 0 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0 0]
[ 0 0 0 0 0 0 0 0 0 0]
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12280#comment:4>
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