Changes between Version 2 and Version 6 of Ticket #16888


Ignore:
Timestamp:
08/28/14 13:38:05 (7 years ago)
Author:
ketzu
Comment:

New commits:

​12755f1Reduced to be a renaming only.

New commits:

​12755f1Reduced to be a renaming only.

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  • Ticket #16888

    • Property Authors changed from to David Mödinger
    • Property Branch changed from to u/ketzu/weak_popov_form_does_not_compute_weak_popov_form
    • Property Commit changed from to 12755f174d1775e53ebf719612f5e984d7120677

  • Ticket #16888 – Description

    v2 v6  
    1 While working on the sage.matrix.matrix2.weak_popov_form method for performance issues I noticed something.
     1While 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.
    22
    33The 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.
    44
    5 While renaming I see this as a chance to correct some (in my opinion) strange behavior of the method:
    6 
    7  1. It takes a parameter ascend but does not relay it to the function (it is entirely ignored)
    8  1. It takes a parameter ascend which is not related to either weak Popov form or row reduced form
    9  1. It returns a 3-touple even though it is only expected to compute the wpf/rrf
    10  1. d of the 3-touple and the sorting is unnecessary computation and should probably not be part of the method.
    11  1. while N is nice to check some things, in my opinion it should only be given if asked for
    12 
    13 Followup ticket for reimplementation of wpf: [ticket:16742 #16742.]
     5Followup ticket for reimplementation of wpf: #16742 and #16896.
    146
    157[MS] T. Mulders, A. Storjohann, "On lattice reduction for polynomial[[BR]]          matrices," J. Symbolic Comput. 35 (2003), no. 4, 377--401
    … …  
    179Comment of weak_popov_form:
    1810
    19   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
     11  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