CODEWITHSUNDEEP
matlab
user1021
user1021

Reputation: 5

More elegant way to write a code

Is there a more elegant way to write this simple code ? The aim is to avoid loops. I tried with repmat for indexes but it didnt work

for j=1:size(C,1);
    for k=1:size(C,2)
        C(j,k)=sum(sum(A([1:j],[1:k]).*B([j:-1:1],[k:-1:1])));
    end
end

EDIT

I modified the code

j=1:size(C,1);
k=1:size(C,2);
B2=rot90(B,2);
C(j,k)=sum(sum(A(1:j,1:k).*B2(end+1-j:end,end+1-k:end)));

It's normal that I have the same value on all the matrix C ?

P.S: I understood that conv2 is the more performant function but I just want to understand where is the problem (why (j, k) doesn't vary) and what's the solution (without loop)

Thank you

Upvotes: 0

Views: 58

Answers (1)

Loamsiada
Loamsiada

Reputation: 454

Isn't this just what conv2(A,B,'same') does?

EDIT

I tested it. It's not exactly the same. But upper left part of conv(A,B) is equal to your C.

Upvotes: 1

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