MATLAB: Add elements in matrix without sum-function

homeworksum

Hello,
How can I sum all the elements in an undefined matrix(the built-in homeworktester puts in its A) without using the sum-function?
This is what I've gotten so far. The result I get is the same element in the matrix multiplied with the numel(A). 
function summa = summa_element(A)
[m,n]=size(A)
a=A(m,n)
summa=0;
for i=1:numel(A)
summa= summa + a
end
end

Best Answer

"The result I get is the same element in the matrix multiplied with the numel(A)."
Well, yes, you never change a inside the loop. So, you're just adding a, numel(A) times. I'm sure you can figure out what you need to do with a inside the loop.
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