MATLAB: Calculation of a double sum

double sum for loop

Hey all!
i want to calculate the double sum over w_ij * v_((2+k*3)+i,(2+l*3)+j). The indices for i should run from -1 to 1 (so -1,0,1), same for j. The indices for k are from 0:893 and for l from 0:356. And w should be -8 if i=j=0, otherwhise it is w=1. i Tried:
for i = -1:1
   for j = -1:1
       if i == 0 & j==0
           w = -8
       else
           w = 1
       end
       for k = 0:893
           for l = 0:356
               sum(w*v((2+k*3)+i,(2+l*3))+j)
           end
       end
   end
   end
    % code
  end
But the results were not as expected. Can you help me? Thanks!

Best Answer

mySum=0;
for i = -1:1
    for j = -1:1
        if i == 0 & j==0
            w = -8;
        else
            w = 1;
        end
        for k = 0:893
            for l = 0:356
                mySum=mySum+( w*v((2+k*3)+i,(2+l*3))+j );
            end
        end
    end
end
disp(['mySum = ' num2str(mySum)]);
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