The Code Does not Compute the other elements of Matrix

Hello,

I am trying to compute value of probabilitiy distribution The formula is ok, code is working I have no error but some values are coming as 0. However I should have a value except zero

Here is my code:

function P = Prob(A_ax,B_by,rho)


d=size(A_ax,1);
m=size(A_ax,4);
bcount=size(A_ax,3);
P = zeros(d,d,bcount,m);

for x=1:bcount %m->bcount
    for y=1:bcount %m->bcount
        for a=1:m %d
            for b=1:m %d
                 for dim=1:d
                    for dim2=1:d
                       %P(dim,dim2,x,y) = real( trace(kron(A_ax(dim,dim2,x,a),B_by(dim,dim2,y,b))*rho));
                          P(a,b,x,y) = real( trace(kron(A_ax(:,:,x,a),B_by(:,:,y,b))*rho));
                     end
                 end
            end
        end
    end
end

As you can see the other values are 0. Where am I doing wrong?

Answer 1

[KSSV]

function P = Prob(A_ax,B_by,rho)


d=size(A_ax,1);
m=size(A_ax,4);
bcount=size(A_ax,3);
P = zeros(d,d,bcount,bcount);   %% Changed here 

for x=1:bcount %m->bcount
    for y=1:bcount %m->bcount
        for a=1:d
            for b=1:d                                                                          
                          P(a,b,x,y) = real( trace(kron(A_ax(:,:,x,a),B_by(:,:,y,b))*rho));                                   
            end
        end
    end
end

[Gözde Üstün]

hello thank you for you answer but the result is still the same :( By the way my A_ax is A_ax(4,4,2,2) and B_by is (4,4,2,2) now

[KSSV]

run the loop till d, a = 1:d, b = 1:d

[Gözde Üstün]

I cannot because since we thought A(4,4,2,2) I have not 4 for the a value so I have an error (A_ax(:,:,x,a))