the competition's expm vs ours

[Jordi Gutiérrez Hermoso]

2008/12/1 Marco Caliari <marco.caliari at univr.it>:
> On my laptop, I got the following results for a 500x500 matrix:
>
> Octave 3.0.3 (with ATLAS): 4.3 seconds
> Octave 3.0.3, removing the extra steps: 4.0 seconds
> Matlab 7.6.0: 1.2 seconds
> Octave 3.0.3, rewriting in a better way the Pade' approximation (and with
> the extra steps): 3.7 seconds
>
> So, I don't think the extra steps produce the difference and they are
> suggested also in "The scaling and squaring method for the matrix
> exponential revisited" by N.J. Higham.

Hrm... Are you using sources that incorporate Jaroslav's indexing
improvements? I guess we could profile Octave to see where the actual
slowdown is instead of guessing...

- Jordi G. H.