MATLAB: Sliced variable issue – variable cannot be classified

optimizationsliced variables

Dear All,
I'm trying to use parallel workers in an optimization problem but I cannot define X and Y as sliced variables. X contains the population, Y contains the fitness values. As the error message says: variable X & Y in a parfor cannot be classified.
First I define X, (it has to be outside the parfor loop otherwise I get new X-es in every single loop); than parfor follows:
parfor t=1:T    
    TmpZ=Func(Z(1,:));TmpX=Func(X(t,:));
    if TmpZ < TmpX
        X(t,:)=Z(1,:); Y(t,1)=TmpZ;
    else
        X(t,:)=X(t,:); Y(t,1)=TmpX;
    end
end
Thanks

Best Answer

I augmented your code a tiny bit to make it executable, and it works fine in MATLAB R2019a, and I checked all the way back to R2013b...
T = 7;
Func = @sum;
Z = rand(1, 3);
X = rand(T, 3);
parfor t=1:T    
    TmpZ=Func(Z(1,:));TmpX=Func(X(t,:));
    if TmpZ < TmpX
        X(t,:)=Z(1,:); Y(t,1)=TmpZ;
    else
        X(t,:)=X(t,:); Y(t,1)=TmpX;
    end
end
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