can this loop be vectorized ?

I am trying to make a function for an histogram to explain the concept to students, is possible to vectorize this loop?

 [x,y]=size(A);                                                  
freq=zeros(256,1); 
for i=1:x
    for j=1:y
        value=A(i,j);
        freq(value+1)=freq(value+1)+1;
    end
end

thanks in advance.

Answer 1

[Guillaume]

Very simply with:

freq = accumarray(A(:), 1, [256, 1]);

[Miguel Reina]

This error is appearing "Error using accumarray First input SUBS must contain positive integer subscripts." the Matrix A contains uint8 values and the size is 594x671

[Guillaume]

Yes, somehow I missed the +1 in your code. The correct answer should be:

freq = accumarray(A(:) + 1, 1, [256, 1]);