From octave-maintainers-request at bevo dot che dot wisc dot edu Tue Jan  6 04:21:26 2004
Subject: Re: benchmarks - sort
From: Schloegl Alois <alois dot schloegl at tugraz dot at>
To: Paul Kienzle <pkienzle at users dot sourceforge dot net>
Cc: octave-maintainers at bevo dot che dot wisc dot edu
Date: Tue,  6 Jan 2004 11:21:15 +0100

Zitat von Paul Kienzle <pkienzle at users dot sourceforge dot net>:

>
> Paul Thomas pointed me to these benchmarks.  Anybody want to do
> something about them?
>
> 	http://www.sciviews.org/other/benchmark.htm
>

...

>
> I.C Matlab 0.89  - Octave 7.77
>      b = sort(a);
>
> Octave's sort is surprisingly slow.  3x worse than any other package
> mentioned.  Anyone know a fast stable sort algorithm?
>


One reason, for the bad performance of the sort algorithm might be the exception
handling of NaNs. See also
http://www.octave.org/octave-lists/archive/bug-octave.2001/msg00047.html

Sorting on the binary level might be helpful, because the bit patterns of the
IEEE754 numbers provide the correct sorting order. This is
-inf < -1 < 0 < 1 < inf < NaN

Just my few thougths.


Alois