Vectorise matrix element multiplication

I want to find a way to vectorise the following operation:

• Take q random elements from the cell Z (which is populated by matrices)
• Multiply them together into a matrix

Here is how I am doing it right now:

combo_matrix = nchoosek(1:N,q);
H = zeros(2^(N/2));
    for i = 1:combo       
        rand_index = randi(size(combo_matrix,1));
        h = eye(2^(N/2));
        for c = 1:q
            h = h*Z{combo_matrix(rand_index,c)}; 
        end
        H = H + h;
        combo_matrix(rand_index,:) = [];
    end
    H = complex(0,1)^(q/2) * H;

Answer 1

[KSSV]

If Z is a matrix. You can replace the loop:

 for c = 1:q
     h = h*Z{combo_matrix(rand_index,c)}; 
 end

with

 c = 1:q ;
 h = prod(Z(combo_matrix(rand_index,c)))