[Octave-bug-tracker] [bug #29768] logm fix

[Rik]

Follow-up Comment #18, bug #29768 (project octave):

I added the rsf2csf function call into the logm script and annotated it with
tic/toc pairs to benchmark the various sections.  The modified logm is
attached.

Benchmarking on a 500x500 random matrix
Schur decomposition (real)
  Elapsed time is 1.505 seconds.
rsf2csf
  Elapsed time is 0.04366 seconds.
sqrtm
  Elapsed time is 2.221 seconds.
Pade approximation
  Elapsed time is 4.461 seconds.
Recovery
  Elapsed time is 0.7695 seconds.

Overall the time on my machine went from 13 seconds to 9 seconds or about a
-30% reduction.  The results also show that the next most time consuming block
which needs work is the Pade approximation.

Using the old eigenvector code the time was 2.665 seconds.  I still like my
suggestion in comment #11 to split the calculation based on tolerance.  If the
user desires maximal accuracy then they can wait for the Pade approximation. 
Otherwise, give them something fast that they can work with.

(file #21075)
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Additional Item Attachment:

File name: logm.m                         Size:3 KB


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