How to make the postions of each circle random?

Hello Matlab Community,

I generated the random number of points (100 users) within 7 different circles (different radius) in square box of 1000 by 1000 meters as shown in figure. Here. the postions of clusters (circles) are fixed in each iterations as I shared in the plots for three iterations. how to make the positions of the cluster (circles) random in each iteration (for example for 10 iterations)?.

Thank You!

the code is here......

% Set the random number generator seed, for reproducibility
rng default
% Number of iterations to run the algorithm
NITER = 3;
% Number of seconds to pause after each figure
NPAUSE = 1;
% Fixed circle parameters
NCIRCLES = 7;
x0  = [100 450 500 650 900 900 800]';
y0  = [700 200 600 500 400 100 850]';
% Number of users
NUSERS = 100; % <--- Change this to 200
for ni = 1:NITER
    userCircle = randi(NCIRCLES,NUSERS,1);
    usersPerCircle = histcounts(userCircle,1:NCIRCLES+1)';
    
    circleRadius = sqrt(usersPerCircle);
    
    figure
    axis square
    set(gca,"Box","on")
    grid on;
    set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
    axis([0 1000 0 1000])
    fontSize = 10;
    xlabel('Position X (1000m)', 'FontSize', fontSize);
    ylabel('Position Y (1000m)', 'FontSize', fontSize);
    title('Random Users Within Circles', 'FontSize', fontSize);
    axis([0 1000 0 1000])
    hold on
    for nc = 1:NCIRCLES
        tnc = 2*pi*rand(usersPerCircle(nc),1);
        rnc = 10*circleRadius(nc)*rand(usersPerCircle(nc),1);
        x = x0(nc) + rnc.*cos(tnc);
        y = y0(nc) + rnc.*sin(tnc);
        h = plot(x,y,".");
        set(h,'MarkerSize',8)
    end
    pause(NPAUSE)
end

[khalid khan]

@the cyclist

Answer 1

[Mathieu NOE]

hello

maybe this ? - as far as I understand you simply want to generate random center position for the circles ?

% Set the random number generator seed, for reproducibility
rng default
% Number of iterations to run the algorithm
NITER = 10;
% Number of seconds to pause after each figure
NPAUSE = 1;
% Fixed circle parameters
NCIRCLES = 7;
% x0  = [100 450 500 650 900 900 800]';
% y0  = [700 200 600 500 400 100 850]';

% Number of users
NUSERS = 100; % <--- Change this to 200
for ni = 1:NITER
    userCircle = randi(NCIRCLES,NUSERS,1);
    usersPerCircle = histcounts(userCircle,1:NCIRCLES+1)';
    
    circleRadius = sqrt(usersPerCircle);
    
    figure(ni)
    axis square
    set(gca,"Box","on")
    grid on;
    set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
    axis([0 1000 0 1000])
    fontSize = 10;
    xlabel('Position X (1000m)', 'FontSize', fontSize);
    ylabel('Position Y (1000m)', 'FontSize', fontSize);
    title('Random Users Within Circles', 'FontSize', fontSize);
    axis([0 1000 0 1000])
    hold on
    
    % create random values for circles position 
    x0  = randi([100,800],NCIRCLES,1);
    y0  = randi([100,800],NCIRCLES,1);


    for nc = 1:NCIRCLES
        tnc = 2*pi*rand(usersPerCircle(nc),1);
        rnc = 10*circleRadius(nc)*rand(usersPerCircle(nc),1);
        x = x0(nc) + rnc.*cos(tnc);
        y = y0(nc) + rnc.*sin(tnc);
        h = plot(x,y,".");
        set(h,'MarkerSize',8)
    end
    pause(NPAUSE)
end

[Khalid Khan]

@Mathieu NOE, Yes exactly perfect, but some of the circles after few iterations are overlapping somehow. How to avoid the overlapping in the circles or how to have a proper gaps between the circles at each iterations?

Thank you so much for the response!!!

[Mathieu NOE]

hello again

so the next trick is that I added a while loop to get enough spacing - here the threshold is set to gap = 3 times the max radius of the data

clc
clearvars

% Set the random number generator seed, for reproducibility
rng default
% Number of iterations to run the algorithm
NITER = 10;
% Number of seconds to pause after each figure
NPAUSE = 1;
% Fixed circle parameters
NCIRCLES = 7;
% x0  = [100 450 500 650 900 900 800]';
% y0  = [700 200 600 500 400 100 850]';

% Number of users
NUSERS = 100; % <--- Change this to 200

   
for ni = 1:NITER
    k = 0;
    userCircle = randi(NCIRCLES,NUSERS,1);
    usersPerCircle = histcounts(userCircle,1:NCIRCLES+1)';
    
%     circleRadius = sqrt(usersPerCircle);
    circleRadius = 10*sqrt(usersPerCircle);
    circleRadius_max = 10*ceil(max(circleRadius*0.1)); % rounded to upper ten's 
    min_gap = 3*circleRadius_max; % min gap between groups  -  adapt factor here (min = 2)
    
    figure(ni)
    axis square
    set(gca,"Box","on")
    grid on;
    set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
    axis([0 1000 0 1000])
    fontSize = 10;
    xlabel('Position X (1000m)', 'FontSize', fontSize);
    ylabel('Position Y (1000m)', 'FontSize', fontSize);
    title('Random Users Within Circles', 'FontSize', fontSize);
    axis([0 1000 0 1000])
    hold on
    
    % create random values for circles position 
    a  = randi([circleRadius_max,1000-circleRadius_max],NCIRCLES,2);
    x0 = a(:,1);
    y0 = a(:,2);
    d0 = sqrt((x0-x0').^2 + (y0-y0').^2);
    min_d0 = min(d0(d0>0));
        
    while min_d0 <= min_gap % retry with new data if condition of gap distance is not met
         a  = randi([circleRadius_max,1000-circleRadius_max],NCIRCLES,2);
         x0 = a(:,1);
         y0 = a(:,2);
        d0 = sqrt((x0-x0').^2 + (y0-y0').^2);
        min_d0 = min(d0(d0>0));
        k = k+1;
    end
    k % shows iterations amount to get a new valid set of coordinates that fullfil the required gap distance

    for nc = 1:NCIRCLES
        tnc = 2*pi*rand(usersPerCircle(nc),1);
%       rnc = 10*circleRadius(nc)*rand(usersPerCircle(nc),1);
        rnc = circleRadius(nc)*rand(usersPerCircle(nc),1);
        x = x0(nc) + rnc.*cos(tnc);
        y = y0(nc) + rnc.*sin(tnc);
        h = plot(x,y,".");
        set(h,'MarkerSize',8)
    end
    pause(NPAUSE)
    hold off
    
end

[Khalid Khan]

@Mathieu NOE Perfectly Okay, Thank you so much for your precous time and response...

[Mathieu NOE]

as always, my pleasure !

would you mind accepting my answer ? tx

[Khalid Khan]

Yes, I would love to accept your answere

[Mathieu NOE]

Make sure you are logged in. If the question has already been closed you will see "Accepted Answer by ____" to the right of your profile picture where the question is asked. If not, then look next to the profile picture of the answerer(s). To the right of each person's answer, in green, you should see a box that says "Accept this answer." Push that button.

[Khalid Khan]

I am already logged in but there is no such options I re-logged in but still no option even I am refreshing the webpage

[Mathieu NOE]

ok no big problem here - don't spend too much time with that !

Answer 2

[Allen]

Just change your x0 and y0 variables to random value vectors and move them to within your primary for loop.

% Set the random number generator seed, for reproducibility
rng default
% Number of iterations to run the algorithm
NITER = 3;
% Number of seconds to pause after each figure
NPAUSE = 1;
% Fixed circle parameters
NCIRCLES = 7;
% x0  = [100 450 500 650 900 900 800]';
% y0  = [700 200 600 500 400 100 850]';
% Number of users
NUSERS = 100; % <--- Change this to 200
for ni = 1:NITER
    % Set x0 & y0 to random values. Using 900 as the maximum as this was
    % the max value previously defined. Use whatever max is appropriate.
    % Also, if x0 & y0 do not need to be integer values, use rand().
    x0 = randi(900,[NCIRCLES,1]);
    y0 = randi(900,[NCIRCLES,1]);
    userCircle = randi(NCIRCLES,NUSERS,1);
    usersPerCircle = histcounts(userCircle,1:NCIRCLES+1)';
    
    circleRadius = sqrt(usersPerCircle);
    
    figure
    axis square
    set(gca,"Box","on")
    grid on;
    set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
    axis([0 1000 0 1000])
    fontSize = 10;
    xlabel('Position X (1000m)', 'FontSize', fontSize);
    ylabel('Position Y (1000m)', 'FontSize', fontSize);
    title('Random Users Within Circles', 'FontSize', fontSize);
    axis([0 1000 0 1000])
    hold on
    for nc = 1:NCIRCLES
        tnc = 2*pi*rand(usersPerCircle(nc),1);
        rnc = 10*circleRadius(nc)*rand(usersPerCircle(nc),1);
        x = x0(nc) + rnc.*cos(tnc);
        y = y0(nc) + rnc.*sin(tnc);
        h = plot(x,y,".");
        set(h,'MarkerSize',8)
    end
    pause(NPAUSE)
end