Use an 'auto' variable from the script in the matlab to simulink solver

Hello,

I would like to modify my simulink solver parameters from an input file loaded by a matlab script.

I would like to modify my simulink solver parameters from an input file loaded by a matlab script. When I add floating numbers, the solver launches without any problem. But if I want to specify in this file the 'auto' function available on Simulink, Simulink does not recognize the variable. Is there a way to give him this information from a workspace variable?

For example this script.m fill in the Simulink solver don't work :

solver.max_step_size = 5e-1;

solver.min_step_size = 5e-3;

solver.initial_step_size = 'auto';

solver.relative_tolerance = 1e-3;

solver.absolute_tolerance = 'auto';

Thnkn for your help,

Answer 1

[Fangjun Jiang]

Yes. This is a problem. A Mathworker might be able to explain why it is done this way. I can provide a workaround solution.

In your script.m, add a line after every parameter that is a string/char array (not a numerical number). For example

solver.initial_step_size = 'auto';
set_param('ModelName','InitialStep', solver.initial_step_size);

Click Help in Configuration Parameters dialog or see this page for the name of the parameters

https://www.mathworks.com/help/simulink/gui/solver-pane.html

[Fangjun Jiang]

More generically, see this link and follow the two links at the bottom.

https://www.mathworks.com/help/simulink/ug/configuration-parameters-dialog-box-overview.html

[Julien]

I tried this solution:

set_param('ModelSimulinkName','MaxStep', 'auto');

It doesn't run.

when I add this first line:

activeConfigObj = getActiveConfigSet('ModelSimulinkName');
set_param(activeConfigObj,'MaxStep', 'auto');

It works.

Thanks for your help, I found a solution to do what I want!