{"id":18087,"date":"2025-06-20T15:47:00","date_gmt":"2025-06-20T19:47:00","guid":{"rendered":"https:\/\/blogs.mathworks.com\/simulink\/?p=18087"},"modified":"2025-09-04T12:55:37","modified_gmt":"2025-09-04T16:55:37","slug":"how-to-programmatically-configure-a-simulink-simulation","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2025\/06\/20\/how-to-programmatically-configure-a-simulink-simulation\/","title":{"rendered":"How to programmatically configure a Simulink simulation?"},"content":{"rendered":"
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Here is another frequently viewed <\/span>MATLAB Answers<\/span><\/a> post:<\/span><\/div>
Set simulation time and fixed step size for a Simulink model from the command line<\/span><\/a><\/div>
While this question asks specifically about <\/span>stop time<\/span><\/a> and solver <\/span>step size<\/span><\/a>, I think this can be generalized to this question: <\/span>How to find the programmatic equivalent of a block or model setting in Simulink?<\/span><\/div>
My answer is: Use <\/span>What's This?<\/span><\/div>

Model Parameters<\/span><\/h2>
In case you never noticed, you can right-click on most configset parameters to see a \"What's This?\" menu being offered:<\/span><\/div>
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Clicking it opens a short description of the setting and the programmatic equivalent:<\/span><\/div>
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Clicking the <\/span>Show more information<\/span> link opens a separate <\/span>What's This Help<\/span> window with more details:<\/span><\/div>
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If you scroll toward the bottom, you will find a table listing everything you need to know about the programmatic use for this setting:<\/span><\/div>
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Block Parameters<\/span><\/h2>
Most blocks parameters also have a What's This?:<\/span><\/div>
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Now that we know how to obtain parameter names and possible values, let's see how to apply them.<\/span><\/div>

Modifying the model<\/span><\/h2>
If you want to modify the model with the new setting value, use <\/span>set_param<\/span><\/a>. For the settings described above, this looks like:<\/span><\/div>
mdl = <\/span>'MyTestModel'<\/span>;<\/span>% The name of the SLX file<\/span><\/span><\/div><\/div>
open_system(mdl);<\/span><\/span><\/div><\/div><\/div>
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Let's check what's the original value using <\/span>get_param<\/span><\/a>, change it, and confirm that it has changed:<\/span><\/div>
get_param(mdl,<\/span>'SolverName'<\/span>)<\/span><\/span><\/div>
ans = <\/span>'VariableStepAuto'<\/div><\/div><\/div><\/div><\/div>
set_param(mdl,<\/span>'SolverName'<\/span>,<\/span>'ode45'<\/span>)<\/span><\/span><\/div><\/div>
get_param(mdl,<\/span>'SolverName'<\/span>)<\/span><\/span><\/div>
ans = <\/span>'ode45'<\/div><\/div><\/div><\/div><\/div><\/div>
The same works for blocks:<\/span><\/div>
blk = <\/span>'MyTestModel\/MyLUT'<\/span>; <\/span>%The path of the block<\/span><\/span><\/div><\/div>
get_param(blk,<\/span>'BreakpointsSpecification'<\/span>)<\/span><\/span><\/div>
ans = <\/span>'Explicit values'<\/div><\/div><\/div><\/div><\/div>
set_param(blk,<\/span>'BreakpointsSpecification'<\/span>,<\/span>'Even spacing'<\/span>);<\/span><\/span><\/div><\/div>
get_param(blk,<\/span>'BreakpointsSpecification'<\/span>)<\/span><\/span><\/div>
ans = <\/span>'Even spacing'<\/div><\/div><\/div><\/div><\/div><\/div>
At this point, you can save your changes using <\/span>save_system<\/span><\/a><\/div>
save_system(mdl);<\/span><\/span><\/div><\/div>

Simulating with different parameter values<\/span><\/h2>
In some cases, you want to simulate the model with different parameter values, but not dirty or modify the model file. For that, I recommend using a <\/span>Simulink.SimulationInput<\/span><\/a> object. Here is an example where I simulate a model with 3 different solvers:<\/span><\/div>
mdl = <\/span>'testStep'<\/span>;<\/span><\/span><\/div><\/div>
open_system(mdl);<\/span><\/span><\/div><\/div><\/div>
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solverChoices = {<\/span>'ode1be'<\/span>,<\/span>'ode3'<\/span>,<\/span>'ode5'<\/span>};<\/span><\/span><\/div><\/div>
N = length(solverChoices);<\/span><\/span><\/div><\/div>
% Creating an array of Simulink.Simulationinput objects<\/span><\/span><\/div><\/div>
in = repmat(Simulink.SimulationInput(mdl),N,1);<\/span><\/span><\/div><\/div>
% specify different solvers for each simulation<\/span><\/span><\/div><\/div>
in = arrayfun(@(i) in(i).setModelParameter(<\/span>'SolverName'<\/span>,solverChoices{i}),1:N);<\/span><\/span><\/div><\/div>
out = sim(in,<\/span>'ShowProgress'<\/span>,<\/span>'off'<\/span>);<\/span><\/span><\/div><\/div>
% Plot results<\/span><\/span><\/div><\/div>
figure; hold <\/span>on<\/span>;<\/span><\/span><\/div><\/div>
arrayfun(@(i) plot(out(i).yout{1}.Values),1:N);<\/span><\/span><\/div><\/div>
legend(solverChoices)<\/span><\/span><\/div>
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Now it's your turn<\/span><\/h2>
How do you find the programmatic way to configure Simulink? Let us know in the comments below.<\/span><\/div>
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