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How can m-file neglect the error "There maybe a singularity in the solution" , produced by Simulink, and does not stop?

Asked by Mohammad Javad Maghsoudi on 13 May 2013

I am running an optimization code in m-file that includes a command to run a Simulink file in every iteration.

sim('Controller_tune_pd',[0:10]);

The program will run Simulink more than 2000 times with different input values. Sometimes these values will cause the singularity in solution and produces the error that stops my m-file.

??? Error using ==> sim Derivative input 3 of 'P_PID/PLANT/Integrator2' at time 0.3750000000000001 is Inf or NaN. Stopping simulation. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances).

Please inform me how may the m-file neglect this error and continue to the program. I am using fixed step size and I can not reduce it. I do not want to remove the error. I want it to be neglected by m-file during running.

1 Comment

Yao Li on 14 May 2013

That is expected. Add memory block to the closed loop which will give an initial value. Also, double check your model to make sure in every step any denominators won't be zero.

Mohammad Javad Maghsoudi

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2 Answers

Answer by Yao Li on 13 May 2013

You can try warning('off','message_id'). However, this warning indicates that there may be a singlarity in certain closed loop. You'd better add a memory block to give an initial value of each closed loop.

0 Comments

Yao Li
Answer by Kaustubha Govind on 14 May 2013

How about using try/catch to catch and ignore the exception thrown by the SIM command.

1 Comment

Saeed on 26 May 2013

Can try/catch command be used for several similar try statements and one catch statements? Ex:

try

   create model1(option1)
   create model2(option2)
   create model3(option3)

catch exception

   error

end

Kaustubha Govind

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