Matrix manipulation
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Hi,
I have a matrix A(1000,6) and i want to write 1's at certain positions say:
i = [785 58 595 389 450 956];
j = [4 6 2 3 5 1];
If I do A(i,j) = 1 it places 1's in the positions "i" of all the columns "j".
But what i want is:
A(i(1),j(1)) = 1
A(i(2),j(2)) = 1
...
A(i(end),j(end)) = 1
Does anybody knows how to do this without having to use a for loop?
1 Comment
Teja Muppirala
on 12 Apr 2011
Is there a compelling reason not to use a FOR loop? A loop will probably do this faster than any non-loop solution (that I can think of anyways).
Accepted Answer
Andrei Bobrov
on 12 Apr 2011
variant
i = [785 58 595 389 450 956];
j = [4 6 2 3 5 1];
A(sub2ind(size(A), i, j)=1;
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