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[Octave-bug-tracker] [bug #53140] Solution of a system of linear equatio
From: |
Marco Caliari |
Subject: |
[Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance. |
Date: |
Wed, 21 Feb 2018 06:06:45 -0500 (EST) |
User-agent: |
Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:58.0) Gecko/20100101 Firefox/58.0 |
Follow-up Comment #17, bug #53140 (project octave):
@Rik: I set xz to b_nr * b_nc and see
octave:10> tic,A\b;,toc
Elapsed time is 64.9591 seconds.
octave:11> tic; [L, U, P, Q, R] = lu (A); xlu = Q * ( U \ ( L \ ( P * ( R \ b
) ) ) ); toc;
Elapsed time is 15.2399 seconds.
that is a factor 4. The same test in matlab R2017b gives
>> tic,A\b;,toc
Elapsed time is 58.941977 seconds.
>> tic; [L, U, P, Q, R] = lu (A); xlu = Q * ( U \ ( L \ ( P * ( R \ b ) ) ) );
toc;
Elapsed time is 33.345003 seconds.
Therefore, it is no more a problem with memory allocation. And there is a
difference between direct-solve and first-factorize, in Matlab too. What I am
not sure of, is whether the factorize function in dSparse.cc performs a long
[L,U,P,Q,R] factorization or not.
@Rik: you should apply your patch to CSparse.cc, too.
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- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., (continued)
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/15
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/16
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/18
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/19
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/19
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/19
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/19
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/19
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/20
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/20
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance.,
Marco Caliari <=
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/23
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., John W. Eaton, 2018/02/23
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/26
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/27
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., John W. Eaton, 2018/02/27
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/27
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/27
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/27
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Marco Caliari, 2018/02/28
- [Octave-bug-tracker] [bug #53140] Solution of a system of linear equations takes forever and hurts OS performance., Rik, 2018/02/28