MATLAB: How to replace two nested for with vectorization

vectorization

How can I write this without loops
[nrows, ncols] = size(A);
for i = 1:nrows
    for j = 1:ncols
        if A(i,j)~=0
            AC(i) = AC(i)+C(i,A(i,j));
        else
            break
        end
    end
end

Best Answer

maxA = max(A(:));
Ccopy = C;
Ccopy(:,maxA+1) = 0;
A(A==0) = maxA+1;
for i = 1 : nrows
  AC(i) = sum( C(sub2ind(size(C), 1:nrows, A(:,j))) );
end
Provided that in code before what was posted, AC was initialized to 0's. If AC was not initialized then replace the code with
error('This is the vectorized equivalent to broken code')
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