Matrix position stored in a variable!

Suppose A=rand(10,10) and I need to access the following elements in A: A(2,3), A(4,5), A(6,7). If the positions are stored in a variable, d=[2 3; 4 5; 6 7], how the matrix elements can be retrieved?

Well, a simple solution is the following for loop.

for i = 1 : size(b, 1)
    A(b(i,1), b(i,2))
end

Any better suggestion?

Answer 1

[Fangjun Jiang]

A=magic(10);
d=[2 3; 4 5; 6 7];
B=A(sub2ind(size(A),d(:,1),d(:,2)))

Update for any size of d

A=rand(2,3,4);
d=[1 2 3;2,3,4;1,2,4];

[m,n]=size(d);
if ndims(A)~=n
    error('Dimension mis-match');
end
ind=mat2cell(d,m,ones(1,n));
B=A(sub2ind(size(A),ind{:}))

[Mohsen Davarynejad]

Thanks Fangjun. I also do not know the dimentions, d can be n*m matrix were n and m are changind during the execution time. so I can not use arguments like d(:,1), d(:,2).

[Fangjun Jiang]

That's tough! See update.

[Mohsen Davarynejad]

Just perfect! Thanks.