[Octave-bug-tracker] [bug #29487] Feature request: svd with 3 output variables should use dgesdd

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?29487>

                 Summary: Feature request: svd with 3 output variables 
should use dgesdd 
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Fr 09 Apr 2010 00:30:04 UTC
                Category: Libraries
                Severity: 3 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.3.51
        Operating System: GNU/Linux

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Details:

I recently checked the sage benchmark page
http://www.sagemath.org/tour-benchmarks.html
and found that matlab and octave are very slow generating 
 [U s V]=svd(A) 
the 1 output version of svd  is as fast as sage.

here my tests, on the same computer of course!:
octave:2> A=randn(1000);
octave:3> tic,[ U s V]=svd(A);toc
Elapsed time is 43.03 seconds.

sage:  m = random_matrix(RDF, 1000)
sage: %time U,s,Vh = m.SVD()
CPU times: user 6.38 s, sys: 0.28 s, total: 6.67 s
Wall time: 13.31 s
sage uses dgesdd.f 

Ciau Erich





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