Re: how to improve sequence plotting speed (to get more fluent animation)?

[Dr.-Ing. Torsten Finke]

Hello Martin, 

...
> Nethertheless I would check what happens if you send exactly the same data 
> via 
> perl to gnuplot as octave produces it - just to see the effect.
...

good tip. I've done that meanwhile, sniffing what octave sends to gnuplot;
this can be done by the undocumented functionality of drawnow() as pointed
out by several mailing list entries: 

   drawnow('x11', '/dev/null', false, 'sniff.dat');

In that debugging file (sniff.dat) one can find: 

   set xtics border in scale  1.4 mirror textcolor rgb "#000000" font ",12";

If I send exactly the same data from perl as has been send by octave, I get
the same stagnating effect (more on x11 terminal, less on wxt). But if I
modify the line above as

   set xtics border in scale  1.4 mirror textcolor rgb "#000000"

plotting starts running fast as it used to. Asking the great oracle about the
keywords "gnuplot set xtics font slow" one can find several discussions about
slowing down plotting, that seems to be caused by the way gnuplot tries to
find appropriate fonts. In fact plotting can be accelerated by a defined font
name as in

   set xtics border in scale  1.4 mirror textcolor rgb "#000000" font 
"helvetica,12";

Unfortunately font names in gnuplot are a nontrivial issue, independence of
platform and driver are desired (of course they are). 

So I am optimistic that plotting can be festened by giving some hints to
gnuplot about font names to be used. Maybe on x11 and wxt that would be
solvable.


> Meanwhile I tested on an old sandbox machine (1 GHz, 512 MB Ram) with 
> opensuse 
> 11.2 your script
> 
> Linux linux-slmv 2.6.31.12-0.2-default #1 SMP 2010-03-16 21:25:39 +0100 i686 
> athlon i386 GNU/Linux
> gnuplot 4.2 patchlevel 5
> GNU Octave, version 3.2.4
> Octave was configured for "i686-pc-linux-gnu".
> (octave installed from packman repositiry)
> 
> and your original octave script. Even with that old machine and wxt as 
> terminal, the animation looks fluent, can something be screwed in your 
> environment?

It seems I suffer from lots of fonts installed on my system. 



Thanks for your advice, since one of my questions got an answer (slowing down
is a gnuplot issue) and best regards



Torsten 




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