Set Matrix Elements based on Coordinates Matrix

Hello

lets say i have a matrix C with Coordinates ... C = [2 3; 4 4];

And a matrix M = zeros(4);

Now i want to set some elements in M based on coordinates from C.

How can i do this without forloop?

Answer 1

[Rik]

You can use sub2ind to convert you coordinate array to linear indices. Then you can use normal indexing to set values.

C = [2 3; 4 4];
M=zeros(4,4);
ind=sub2ind(size(M),C(:,1),C(:,2));
M(ind)=1;
disp(M)

     0     0     0     0
     0     0     1     0
     0     0     0     0
     0     0     0     1