#16888: weak popov form does not compute weak popov form
-------------------------------------+-------------------------------------
Reporter: ketzu | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.4
Component: linear algebra | Resolution:
Keywords: weak-popov-form | Merged in:
matrix | Reviewers:
Authors: David Mödinger | Work issues:
Report Upstream: N/A | Commit:
Branch: | 12755f174d1775e53ebf719612f5e984d7120677
u/ketzu/weak_popov_form_does_not_compute_weak_popov_form| Stopgaps:
Dependencies: |
-------------------------------------+-------------------------------------
Changes (by {'newvalue': u'David M\xf6dinger', 'oldvalue': ''}):
* author: => David Mödinger
Old description:
> While working on the sage.matrix.matrix2.weak_popov_form method for
> performance issues I noticed something.
>
> The weak Popov form as defined in [MS] is not computed by this method.
> The other references do not call this form weak Popov form, it is a les
> restrictive definition for a certain row reduced form of matrix.
>
> While renaming I see this as a chance to correct some (in my opinion)
> strange behavior of the method:
>
> 1. It takes a parameter ascend but does not relay it to the function (it
> is entirely ignored)
> 1. It takes a parameter ascend which is not related to either weak Popov
> form or row reduced form
> 1. It returns a 3-touple even though it is only expected to compute the
> wpf/rrf
> 1. d of the 3-touple and the sorting is unnecessary computation and
> should probably not be part of the method.
> 1. while N is nice to check some things, in my opinion it should only be
> given if asked for
>
> Followup ticket for reimplementation of wpf: [ticket:16742 #16742.]
>
> [MS] T. Mulders, A. Storjohann, "On lattice reduction for
> polynomial[[BR]] matrices," J. Symbolic Comput. 35 (2003), no.
> 4, 377--401
>
> Comment of weak_popov_form:
>
> OUTPUT:[[BR]] [[BR]] A 3-tuple !`(W,N,d)` consisting of:[[BR]]
> [[BR]] 1. !`W` - a matrix over !`k(x)` giving a weak the Popov
> form of self[[BR]] 2. !`N` - a matrix over !`k[x]` representing
> row operations used to[[BR]] transform !`self` to !`W`
> [[BR]] 3. !`d` - degree of respective columns of W; the degree
> of a column is[[BR]] the maximum of the degree of its elements
New description:
While working on the sage.matrix.matrix2.weak_popov_form (for
sage.matrix.matrix_misc.weak_popov_form applies the same) method for
performance issues I noticed something.
The weak Popov form as defined in [MS] is not computed by this method. The
other references do not call this form weak Popov form, it is a les
restrictive definition for a certain row reduced form of matrix.
Followup ticket for reimplementation of wpf: #16742 and #16896.
[MS] T. Mulders, A. Storjohann, "On lattice reduction for polynomial[[BR]]
matrices," J. Symbolic Comput. 35 (2003), no. 4, 377--401
Comment of weak_popov_form:
OUTPUT:[[BR]] [[BR]] A 3-tuple !`(W,N,d)` consisting
of:[[BR]] [[BR]] 1. !`W` - a matrix over !`k(x)` giving a
weak the Popov form of self[[BR]] 2. !`N` - a matrix over
!`k[x]` representing row operations used to[[BR]] transform
!`self` to !`W` [[BR]] 3. !`d` - degree of respective
columns of W; the degree of a column is[[BR]] the maximum of
the degree of its elements
--
Comment:
New commits:
||[http://git.sagemath.org/sage.git/commit/?id=12755f174d1775e53ebf719612f5e984d7120677
12755f1]||{{{Reduced to be a renaming only.}}}||
----
New commits:
||[http://git.sagemath.org/sage.git/commit/?id=12755f174d1775e53ebf719612f5e984d7120677
12755f1]||{{{Reduced to be a renaming only.}}}||
--
Ticket URL: <http://trac.sagemath.org/ticket/16888#comment:6>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
