#16632: Double creation, can be recycled
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Reporter: tscrim | Owner: tscrim
Type: defect | Status: needs_review
Priority: major | Milestone: sage-duplicate/invalid/wontfix
Component: linear | Resolution:
algebra | Merged in:
Keywords: matrix | Reviewers:
mutation | Work issues:
Authors: | Commit:
Report Upstream: N/A | Stopgaps:
Branch: |
Dependencies: |
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Changes (by tscrim):
* status: new => needs_review
* milestone: sage-6.3 => sage-duplicate/invalid/wontfix
Old description:
> In 6.3.beta5 we have
> {{{
> sage: A = matrix(QQ, [[ 4, -2, 4, 2],
> ....: [-2, 10, -2, -7],
> ....: [ 4, -2, 8, 4],
> ....: [ 2, -7, 4, 7]])
> sage: A.indefinite_factorization()
> (
> [ 1 0 0 0]
> [-1/2 1 0 0]
> [ 1 0 1 0]
> [ 1/2 -2/3 1/2 1], (4, 9, 4, 1)
> )
> sage: A
> [ 4 -2 4 2]
> [-2 10 -2 -7]
> [ 4 -2 8 4]
> [ 2 -7 4 7]
>
> sage: B = matrix(QQ, [[ 4, -2, 4, 2],
> ....: [-2, 10, -2, -7],
> ....: [ 4, -2, 8, 4],
> ....: [ 2, -7, 4, 7]])
> sage: B.set_immutable()
> sage: B.indefinite_factorization()
> (
> [ 1 0 0 0]
> [-1/2 1 0 0]
> [ 1 0 1 0]
> [ 1/2 -2/3 1/2 1], (4, 9, 4, 1)
> )
> sage: B
> [ 1 0 0 0]
> [-1/2 1 0 0]
> [ 1 0 1 0]
> [ 1/2 -2/3 1/2 1]
> }}}
>
> Actually the problem stems from the output of `change_ring()`:
> {{{
> sage: A.change_ring(QQ) is A
> False
> sage: B.change_ring(QQ) is B
> True
> }}}
New description:
Double creation of #16633.
--
--
Ticket URL: <http://trac.sagemath.org/ticket/16632#comment:1>
Sage <http://www.sagemath.org>
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