How can I vectorize these for loops?
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Newbie here. I was wondering if there was a way to vectorize these for loops, or simply to change it to make it faster? Any help would be appreciated. Thank you!
m = zeros(50);
d = zeros(50);
for i = 1:size(m,1)
for n = 1:size(m,2)
try d(i,n) = sum(m(i-1:i+1,n-1:2:n+1),'all') + sum(m(i-1:2:i+1,n),'all');
catch, continue
end
end
end
What it does is scan the matrix positions immediately surrounding each matrix position being looped through and sums the values. It doesn't work at the edges or the corners, which is what the try, catch statement is for. Thanks again.
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Mohammad Sami
2020년 5월 28일
What you are trying to do is 2D convolution. There is a function conv2 that will allow you to do this.
m = ones(50);
filter = ones(3);
filter(2,2) = 0;
% 3x3 filter with excluding the center.
d = conv2(m,filter,'same');
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