Simulink FastRestart doesnt change output

Hey Guys,

i have a simulink model in a for loop. Every Iteration i change parameters in my system. If i run the system without Fast Restart, it changes it outcome as it should. But when i activate FastRestart in my model the output is always the same.

My Code is:

for k=1:3
    alpha = [50-k,100+k,125-k,85+k]; 
    s = [3-0.01*k,4+0.01*k,4-0.01*k]; 
    t = [3+0.01*k,4-0.01*k,4+0.01*k];
    
    geometrics = getGeometrics(alpha,s,t); %returns a strucArray. The Geometrics are used as length and angle Parameters in the Simulation

        %start simulation
        simOut = sim('Model.slx','CaptureErrors','on','SrcWorkspace','current');

        %Solution
        pos1 = simOut.xx.data;
        disp(['Position: ' num2str(pos1), 'cm')]);
end   

% The Display in normal like 1cm, 2cm, 3cm and in FastRestart 1cm, 1cm, 1cm 

I have no idea why my output doesnt change in FastRestart. In

https://de.mathworks.com/help/simulink/ug/fast-restart-workflow.html

it is written that all my blocks must support ModelOperatingPoint but i dont know how to check that either.

[Ahmed Fahmy]

I have a similar issue reported here https://www.mathworks.com/matlabcentral/answers/1653390-simscape-resistance-randomization-does-not-occur-when-running-simulation-with-fast-restart but it is more with random tolerance of simscape components

But I tried something similar to what you did with fast restart and it worked fine with me. So I am curious to know how are you passing the swept parameters to your model? are you using from_work_space block or just using them as mask parameters of some blocks?

[NV]

I have this same problem, did you manage to find a solution?

[Ahmed Fahmy]

I don't recall I had a workaround.

Answer 1

[Kothuri]

Hi Marcus Heßeling,

The issue you are facing is because in Fast Restart it is not reinitializing parameters that are changed in the MATLAB workspace. When Fast Restart is enabled, Simulink does not reload model parameters from the workspace for each simulation run unless explicitly told to do so.

You cn try the below steps in Fast Restart:

• To reload workspace variables, you need to explicitly update them using "set_param()" before running the simulation. You can try the below code

for k = 1:3
    alpha = [50-k, 100+k, 125-k, 85+k]; 
    s = [3-0.01*k, 4+0.01*k, 4-0.01*k]; 
    t = [3+0.01*k, 4-0.01*k, 4+0.01*k];

    geometrics = getGeometrics(alpha, s, t); % Get updated parameters

    % Update parameters in the model
    set_param('Model', 'FastRestart', 'on'); % Ensure Fast Restart is on
    set_param('Model', 'SimulationCommand', 'update'); % Ensure parameters are updated
    
    % Start simulation
    simOut = sim('Model', 'CaptureErrors', 'on', 'SrcWorkspace', 'current');

    % Solution
    pos1 = simOut.xx.data;
    disp(['Position: ' num2str(pos1), 'cm']);
end

• You can also set the variables inside the "model workspace", which can update automatically during Fast Restart.
• To check if all the blocks support "Fast Restart", you can try the below command

get_param('Model', 'OperatingPointCompliance')

• This will show whether your blocks support fast restart.
• If you get "Unknown" or "Unsupported", then some blocks in your model do not support fast restart.