Re: Maxwell's density function grinds Octave

[Henry F. Mollet]

Why is a problem of running out of colors rather than only a problem of too
fine a grid?  I only get two colors, red outside and green inside of what
can be seen of the saddle.
GNU Octave, version 2.1.46 (powerpc-apple-darwin6.6)
G N U P L O T Version 3.8i patchlevel 0
Henry


on 8/21/04 4:40 AM, Paul Thomas at address@hidden wrote:

> Reduce the mesh dimensions by a factor 20x10!
> 
> ie.
> 
>> V = 0:20:2000;
>> t = 273.15:10:1073.15;
> 
> octave did OK with the original but Gnuplot crashed!  Matlab R13 does not do
> well with the original mesh either.  Both run out of colours for the plot.
> 
> Paul T
> 
> ----- Original Message -----
> From: "Gad Abraham" <address@hidden>
> To: <address@hidden>
> Sent: Saturday, August 21, 2004 10:18 AM
> Subject: Maxwell's density function grinds Octave
> 
> 
>> Hi,
>> 
>> I've been trying to plot Maxwell's speed distribution equation for ideal
>> gases on Octave, using the following code (adapted from a matlab script
>> on http://chemistryresources.tripod.com/physical/maxwell.txt):
>> 
>> function surf(varargin) mesh(varargin{:}); endfunction
>> 
>> M = 32e-3;
>> R = 8.31451;
>> 
>> V = 0:1:2000;
>> t = 273.15:1:1073.15;
>> 
>> [v, T] = meshgrid(V, t);
>> 
>> f = 4*pi*((M./(2*pi*R.*T)).^(3/2)).*(v.^2).*exp(-M.*(v.^2)./(2*R*T));
>> 
>> surf(v,T,f);
>> 
>> xlabel('v');
>> ylabel('T');
>> zlabel('f');
>> 
>> 
>> The problem is that on my rather fast machine (AthlonXP2800, 768MB RAM),
>> this grinds away for almost 10 minutes, and the end result is a gnuplot
>> window with a only few tiny lines in it.
>> 
>> I'm using Octave2.1, gnuplot 4.0, on Debian Linux.
>> 
>> 
>> Any advice?
>> 
>> 
>> Thanks,
>> Gad
>> 
>> -- 
>> http://chookies.homeunix.org
>> 
>> 
>> 
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> 
> 
> 
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> Octave is freely available under the terms of the GNU GPL.
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Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
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