function?[XYXt]=generate_two_moons（rwdNseeddisplay）
%?GENERATE_TWO_MOONS?
%?INPUTS:
%?r:?radius?of?2?moons
%?w:?width?of?the?2?moons
%?d:?distance?between?the?two?moons
%?N:?number?of?samples?to?generate?in?each?moon
%?display:?1?shows?the?2moons?after?generation?0?no?display
%
%?OUTPUTS:
%?X:?2N?X?2?matrix?
%?Y:?2N?X?1?vector?--?+1?for?top?moon?-1?for?bottom?moon
%?Xt:?uniformly?spaced?points?on?a?grid
%
%?Vikas?Sindhwani?（vikass@cs.uchicago.edu）


%?top?moon
rand（‘seed‘seed）;
r?=?r+w/2;

%?randomly?pick?radial?coordinate?between?r-w?and?r?
R=（r-w）*ones（N1）?+?rand（N1）*w;
%?randomly?pick?the?angular?coordinate
theta=rand（N1）*pi;

X=[R.*cos（theta）?R.*sin（theta）];
Y=ones（N1）;

%?bottom?moon

%?randomly?pick?radial?coordinate?between?r-w?and?r?
R=（r-w）*ones（N1）?+?rand（N1）*w;
%?randomly?pick?the?angular?coordinate
theta=pi+rand（N1）*pi;

%?move?x?coordinate?by?y?coordinate?down?by?d
del_x=r-（w/2）;
del_y=-d;
x=[R.*cos（theta）+del_x?R.*sin（theta）+del_y]
y=-ones（N1）;

X=[X;x];
Y=[Y;y];

r=r-w/2;

if?display==1
???plot（X（Y==11）X（Y==12）‘r+‘‘MarkerSize‘8）;?hold?on;
???plot（X（Y==-11）X（Y==-12）‘bx‘‘MarkerSize‘8）;?
???axis?tight;
???axis?equal;
???title（[‘2?moons?dataset?:?r=‘?num2str（r）?...
???????‘?w=‘?num2str（w）?‘?d=‘?num2str（d）?‘?N=‘?num2str（N）]）;
end

?xmin=min（X（:1））;?
?xmax=max（X（:1））;?
?ymin=min（X（:2））;?
?ymax=max（X（:2））;
?
[xy]?=?meshgrid（xmin:（xmax-xmin）/50:xmaxymin:（ymax-ymin）/50:ymax）;
Xt=[reshape（xprod（size（x））1）?reshape（yprod（size（y））1）];