Setting up parasite model

I am trying to set up a parasite model that represents a grid of 200*200 cells.

In this grid there has to be 20 parasites and 20 food at random locations. I used this code:

fxPos=randi(200,20,1); fyPos=randi(200,20,1);

food=[fxPos fyPos];

pxPos=randi(200,20,1); pyPos=randi(200,20,1); pLifespan=randi(15,20,1); parasites=[pxPos pyPos pLifespan];

What I am stuck on is how can I make certain that no two particles end up on the same position on the grid.

Answer 1

[Star Strider]

One way you can check to be certain that no two positions are the same is to be certain that the positions are unique:

foodRows = 0;
while foodRows < 20
    fxPos=randi(200,20,1);
    fyPos=randi(200,20,1);

      food=[fxPos fyPos];

      [Ufood,~,ix] = unique(food, 'rows');
      foodRows = size(Ufood,1)
  end

That may be the easiest (and likely most efficient) option.