Fmincon issue: Failure in initial objective function evaluation. FMINCON cannot continue.

I am trying to minimize the absolute differences between frequencies in ETABSV21 through API using a self created objective function. But with the code i have this error is showed: Failure in initial objective function evaluation. FMINCON cannot continue.

Bellow is the function code

function fo=objetivo(x)
global SapModel PropFrame PropMaterial Analyze AnalysisResultsSetup Results


PropMaterial.SetMPIsotropic('conc_losa',x(1)*24855.58,0.2,0.0000099);
PropMaterial.SetMPIsotropic('conc_muros',x(2)*24855.58,0.2,0.0000099);



Analyze.RunAnalysis();
AnalysisResultsSetup.DeselectAllCasesAndCombosForOutput;
AnalysisResultsSetup.SetCaseSelectedForOutput('MODAL');


NumberResults = 0;
LoadCase      = {''};
StepType      = {''}; 
StepNum       = 0;
Period        = 0;
Frequency     = 0; 
CircFreq      = 0;
EigenValue    = 0;


[ret,NumberResults,~,~,~,Period,Frequency,~,~]=Results.ModalPeriod(NumberResults, LoadCase, StepType, StepNum, Period, Frequency, CircFreq, EigenValue)


frecuencias=double(Frequency)

fo=mean(abs((frecuencias(1)-2.5781))/2.5781 + abs((frecuencias(3)-2.7930))/2.7930+abs((frecuencias(2)-4.8438))/4.8438);


xo  = x;
save('xo', 'xo')
end

NOW this is how i call the function

LI=[20000.58/24855.58]; 
CI=[24855.58/24855.58];
LS=[33855.58/24855.58];
opciones=optimoptions('fmincon','Algorithm','sqp','Display','iter','PlotFcn',@optimplotfval)
[x,fval,~] = fmincon(@objetivo,CI,[],[],[],[],LI,LS,[],opciones);

[Torsten]

I suggest you try

fo = objetivo(CI)

right before the call to "fmincon" and see what is returned in "fo".

It should be some scalar value in order to let "fmincon" work.

[Cristopher Angola Ararat]

It appears that like that the initial error is corrected. Now is this:

Dot indexing is not supported for variables of this type.

Error in objetivo (line 5)

PropMaterial.SetMPIsotropic('conc_losa', x(1)*24855.58, 0.2,0.0000099);

[Torsten]

You only have one unknown CI = x(1). Thus refering to x(2) in the line

PropMaterial.SetMPIsotropic('conc_muros',x(2)*24855.58,0.2,0.0000099);

makes no sense.

[Cristopher Angola Ararat]

Thank you so much, however,

I do have this:

LI=[20000.58/24855.58, 20000.58/24855.58];

CI=[24855.58/24855.58, 24855.58/24855.58];

LS=[33855.58/24855.58, 33855.58/24855.58];

Its still the same error

Answer 1

[Torsten]

It seems that

PropMaterial.SetMPIsotropic

cannot be accessed in "objetivo".

Are you sure it has been written into the global variable "PropMaterial" somewhere before in your code ?

What do you get if you type

PropMaterial

right after

function fo=objetivo(x)
global SapModel PropFrame PropMaterial Analyze AnalysisResultsSetup Results

?

Maybe empty ?

[Cristopher Angola Ararat]

That was the thing, i have to define the global variables both in the script like in the function. Thank you for everything