How I can vectorize the next code?

Hello. M is a matrix and v and w are vectors of the same length containing some indices of M. I want to vectorize the following code (without using loops)

for i=1:length(v);
  M(v(i),w(i)) = 1;
end

Answer 1

[Azzi Abdelmalek]

M=magic(5);  % example
v=1:2;
w=3:4
idx=sub2ind(size(M),v,w)
M(idx)=1

Answer 2

[Image Analyst]

You simply do

M(v, w) = 1;

Here's proof:

M = magic(10)
v = randi(10, 5,1)
w = randi(10, 5,1)
M(v,w) = 1

[Alfredo Rojas]

This code assigns 1 to each combinations of indices on v and w

[Image Analyst]

Ah, you're right, that won't work (though it seems like it would). Use Azzi's code then.

Answer 3

[Andrei Bobrov]

M = randi([100,300],10);
v = randi(10,7,1);
w = randi(10,7,1);

M(v + size(M,1)*(w-1)) = 1