From octave-maintainers-request at bevo dot che dot wisc dot edu Tue Jan  6 13:38:17 2004
Subject: Re: benchmarks - sort
From: Schloegl Alois <alois dot schloegl at tugraz dot at>
To: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
Cc: octave-maintainers at bevo dot che dot wisc dot edu
Date: Tue,  6 Jan 2004 20:38:00 +0100

Zitat von "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>:

> On  6-Jan-2004, Schloegl Alois <alois dot schloegl at tugraz dot at> wrote:
>
> | 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
>
> Can you explain precisely what you mean by sorting on the binary
> level?
>
> jwe
>


Instead of floating point comparison, one could use integer comparision.
Because the exponent is in the Most Significant Bytes, a comparison based

This would require casting floating point numbers into integers (signed long
long should do), and casting does not take any effort in C.


Alois