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I estimated a non-linear ARX model with the sytem identification toolbox in matlab and tried to simulate the response to a validation data set. Unfortunatly the response seems to be not stable and doesn't lead to the results obtained from the compare fcn.

nlarx2 is my model:

opt3=simOptions("InputOffset",4,"InitialCondition",IO); sim(nlarx2,Data_val1.InputData,opt3)

The initial condition is obtained from the estimation data set from the compare fcn

I dont know if I have to add the discretness of the model or what else could be wrong. The error message says:

">> sim(nlarx2,Data_val1.InputData,opt3) Warning: Model output became non-finite at time 58 seconds. Aborting the rest of the simulation.

In idnlarx/utsim>localInfNanWarn (line 79) In idnlarx/utsim (line 61) In idnlarx/sim_ (line 129) In idmodel/sim (line 113) "

I obtain a figure, but not a useful one.

Thank you for your help

Fibaro
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  • I found a simple solution for the problem. I used the command findStates to obtain my initial conditions. 'IO = findstates(nlarx,Data_estimation,inf); ' For that I just used the estimation Data set I took to estimate my non-linear ARX model in the first place. – Fibaro Jan 11 '23 at 15:11

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