MATLAB: Displaying random numbers as a graph

displayrandom numbers

I am generating random numbers with the rejection sampling, like in this picture. How can I see my generated random numbers as points, like in this picture?

Best Answer

One approach is to use the inpolygon function:

x = linspace(0, 10);
y = exp(-(x-5).^2)*0.2;
r = rand(1000,2).*[10 0.25];
[in,on] = inpolygon(r(:,1),r(:,2), x, y);
figure
plot(x,y)
hold on
plot(r(:,1), r(:,2),'.r')
plot(r(in,1), r(in,2), '.g')
hold off

producing:

Experiment with it to get the result you want.

Related Solutions

MATLAB: Simple plot question (:,1)

Here your y is having two columns and many rows.

Here you are considering y(:,1) in x-axis and y(:,2) in y-axis in the plot.

If you use plot(y,'r'), then two column will plot in y-axis and x-axis will be some random value.

if you want more clear idea in plotting just check this different plots.

y=rand(10,2);
plot(y(:,1),'r');
plot(y(:,2),'r');
plot(y,'r');
x=1:10; % here x-axis assumed from 1 to 10
plot(x,y,'r');
plot(x,y(:,1),'r');
plot(x,y(:,2),'r');

MATLAB: Create a box around points and use in inpolygon

load("polygon1_x.mat") ; 
load("polygon1_y.mat") ; 
load("lon.mat") ; 
load("lat.mat") ; 
% remove Nan's from the data 
xv = polygon1_y ; yv = polygon1_x ; 
xv(isnan(xv)) = [] ;
yv(isnan(yv)) = [] ;
%
loncoord = zeros([],1) ; 
latcoord = zeros([],1) ;
count = 0 ; 
for i = 1:length(lon)
  i
    % make grid around (lon,lat)
  x = lon(i)-0.5:0.5:lon(i)+0.5 ; 
  y = lat(i)-0.5:0.5:lat(i)+0.5 ; 
  [X,Y] = meshgrid(x,y) ; 
  [in,on] = inpolygon(X(:),Y(:),xv,yv);         % Logical Matrix
  inon = in | on;                                             % Combine ‘in’ And ‘on’
  idx = find(inon(:));                                        % Linear Indices Of ‘inon’ Points
  
  if any(idx)
    count = count+1 ; 
    loncoord(count) = lon(i);                                        % Y-Coordinates Of ‘inon’ Point
    latcoord(count) = lat(i) ;   
  end
end
plot(polygon1_y,polygon1_x,'b')
hold on
plot(loncoord,latcoord,'*r')

Best Answer

Related Solutions

MATLAB: Simple plot question (:,1)

MATLAB: Create a box around points and use in inpolygon

Related Question