issue in matrix multiplication
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G=[1 1 1 1 1 0 0 0 1 0 0 0; 0 0 1 1 0 0 0 1 0 1 0 0; 1 1 1 0 1 0 0 1 0 0 1 0; 1 0 0 1 1 1 0 1 0 0 0 1];
m=[1 0 1 0]
how to multiply them??
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Youssef Khmou
2013-12-4
编辑：Youssef Khmou
2013-12-4
G is 4x12 and m is 1x4, then two possibilities :
m*G
G'*m'
You do not get binary result because of the multiplication cij=sum a_ik b_kj there is an addition. you can get binary results if the matrices have the same dimensions and you use Hadamard product :
m=m'
M=zeros(4,12);
for n=1:12
M(:,n)=m;
end
M.*G
更多回答（4 个）
Wayne King
2013-12-4
编辑：Wayne King
2013-12-4
G=[1 1 1 1 1 0 0 0 1 0 0 0; 0 0 1 1 0 0 0 1 0 1 0 0; 1 1 1 0 1 0 0 1 0 0 1 0; 1 0 0 1 1 1 0 1 0 0 0 1];
m=[1 0 1 0];
out = m*G;
How else would you presume to multiply them?
Walter Roberson
2013-12-4
G is 12 x 4, and m is 1 x 4, so there is no direct way to multiply them. You can, however, use
G * m.'
to get 12 x 1, or you can use
m * G.'
to get 1 x 12
Possibly what you want is
G .* repmat(m.', 1, size(G,2))
sixwwwwww
2013-12-4
mary you can get desired output as follows:
G = [1 1 1 1 1 0 0 0 1 0 0 0; 0 0 1 1 0 0 0 1 0 1 0 0; 1 1 1 0 1 0 0 1 0 0 1 0; 1 0 0 1 1 1 0 1 0 0 0 1]';
m = [1 0 1 0];
idx = find(m);
result = zeros(1, size(G, 1));
for i = 1:size(G, 1)
result(i) = sum(G(i, min(idx):max(idx)));
end
disp(result)
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