Re: Speed of lsim

[Henry F. Mollet]

[Henry-Mollets-Computer:~] mollet% octave
GNU Octave, version 2.1.35 (powerpc-apple-darwin6.2).
Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 John W. Eaton.
This is free software with ABSOLUTELY NO WARRANTY.
For details, type `warranty'.

octave:1> sys = tf2sys(1, [1,1]);
octave:2> t = linspace(0,10,1001)';
octave:3> u = ones(1001,1);
octave:4> tic; lsim(sys,u,t); toc
ans = 209.93

On iMac with 400 MHz PowerPC G3.
Henry



on 7/29/03 6:38 AM, Geraint Paul Bevan at address@hidden wrote:

> SToyama wrote:
>> Hi. I am a beginner of Octave, and I need some help to accelerate
>> "lsim".
>> As I want to simulate the response of a linear time-invariant state
>> equation 
>> to the arbitrary input signal, I tried to use "lsim". But I feel it's
>> too slow.
>> For example, it took about a minute to solve the step response of a
>> simple 
>> 1st order lag system, 1/(1+s).
>> My Octave is version 2.1.36, my PC has Pentium-III 1.2GHz and 256MB-RAM
>> and OS is Windows XP Pro.
>> I'm waiting for your good advice.
>> Thanks.
>> st
>> 
> 
> That is very slow, using octave 2.1.50 on an i686 running Debian/Linux
> it takes less than a second:
> 
> octave:1> sys = tf2sys(1, [1,1]);
> octave:2> t = linspace(0,10,1001)';
> octave:3> u = ones(1001,1);
> octave:4> tic; lsim(sys,u,t); toc
> ans = 0.33443
> 
> Are you using a pre-packaged version of octave or did you compile it
> yourself?
> 



-------------------------------------------------------------
Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
How to fund new projects:  http://www.octave.org/funding.html
Subscription information:  http://www.octave.org/archive.html
-------------------------------------------------------------