implementing fmincon() when the variables are matrix

Hey guys,

I want to implement fmincon() for this problem: I am minimizing an objective function with respect to some variables. the variable has the following format

X = cell(max(I(:)), numel(I), numel(I), numel(M), max(M(:)))) and inside each cell I have a Nt*Nr matrix. The goal is to find the optimal values of each matrix.

I defined the symbolic array of X (I am not sure if I am doing it correctly, though) and pass it to my objective function to calculate the objective function as follows:

X = cell2sym(cell(max(I(:)), numel(I), numel(I), numel(M), max(M(:))));

objfun = f(X)

but, I get the following error: Brace indexing is not supported for variables of this type.

while I am able to get the value of f(X0) without any issue. Could anyone please kindly explain what the problem is?

Thanks in advance