How to adjust concrete location od facilities in Sales Allocation Model?

In the model that is set on https://www.mathworks.com/help/optim/ug/factory-example-problem-based.html the location of facilities is random.

rng(1) % for reproducibility

N = 20; % N from 10 to 30 seems to work. Choose large values with caution.

N2 = N*N;

f = 0.05; % density of factories

w = 0.05; % density of warehouses

s = 0.1; % density of sales outlets

F = floor(f*N2); % number of factories

W = floor(w*N2); % number of warehouses

S = floor(s*N2); % number of sales outlets

xyloc = randperm(N2,F+W+S); % unique locations of facilities

[xloc,yloc] = ind2sub([N N],xyloc);

So i was wondering is there any way to set concrete value of x and y (which i am entering) for each facilities? Thanks a lot!