How to multiply values to specific elements in a matrix?
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I have a matrix
A=[ 1 0 0 0;
0 1 0 0;
1 0 0 0;
0 0 0 1 ]
I want to multiply an array B= [1,5,7,8] to wherever 1's are in matrix A. Resultant matrix is:
A = [1 0 0 0;
0 5 0 0 ;
7 0 0 0;
0 0 0 8]
How can I do it in vectorized form? Please note that number of ones in input matrix A will always equal the length of array B
Thanks!
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the cyclist
le 19 Nov 2016
Modifié(e) : the cyclist
le 19 Nov 2016
In MATLAB 2016b (and presumably later yet-to-be-released versions), you can just write
A.*B'
In earlier versions, you need to use bsxfun:
bsxfun(@times,A,B')
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Roger Stafford
le 20 Nov 2016
Assuming the number of ones in A is equal to the length of B,
At = A.’;
At(At==1) = B;
A = At.’;
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