Speeding up parted simulation

On Wed, 27 May 2009 08:19:02 +0000 (UTC), "pierre " <...@yopmail.com

Hello,

Thanks to 'sim' function, I run a simulation on a total timespan of 1s, from Matlab.
Today, this simulation is actually parted in 10 simulations of 0.1s. At the end of each 0.1s interval, I :
- get in Matlab the simulation FinalState, xf_sml ;
- get the variables sent to Matlab Workspace by 'To Workspace' Simulink blocks ;
- process these data in my main Matlab .m file
. polynomial evaluation,
. matrix computing,
. data reshaping {concatenation, extraction, etc.},
. state-space matrix updating ;
- runs a new 0.1s simulation, using previous FinalState as new IntialState x0_sml, in order to keep simulation "continuity".

Here's a shortened version of my script :

timespan = 10; % total timespan
T = 0.1; % elementary timepsan
Te = 1e-4; % sample time
for i=0:(round(timespan/T)-1)
inter_sml = [i, i+1]* T;
options_sml = simset('Solver', 'FixedStepDiscrete', 'FixedStep', ...
Te, 'OutputVariables', 'x', 'SaveFormat', 'StructureWithTime', ...
'InitialState', x0_sml, 'FinalStateName', 'xf_sml');
[t, x, y] = sim(mymodel, inter_sml, options_sml);
x0_sml = xf_sml; % x0_sml(i+1)=xf_sml(i)
end;

Problem : this code is too slow, especially each call to 'sim' function, whose self time is about 10 times the simulated timespan (according to profiler).
Launched alone (outside Matlab) thanks to 'Start simulation' button [or with a unique 'sim' call on 10s without any return to Matlab every 0.1s], this model runs twice faster than real-time. What lets me think the reason for this slowness is elsewhere (maybe could the exchange of variables between Simulink to Matlab be guilty?).

Any ideas for speeding up this simulation?
Either re-thinking the whole solution or thinking about a way to speed up lazy 'sim'...

Thanks for your help,
pierre