MATLAB：生成一個雙環二維數據

N = 200;

rA = ones(1,N)*2+0.5*rand(1,N);
rB = ones(1,N)+0.5*rand(1,N);

thetaPos = pi*(2.*[1:N]./N);
zeroA = [0,0];
zeroB = [0,0];

feaA = [rA.*cos(thetaPos)+zeroA(1); rA.*sin(thetaPos)+zeroA(2)]'; %'
feaB = [rB.*cos(thetaPos)+zeroB(1); rB.*sin(thetaPos)+zeroB(2)]'; %'

fea = [feaB;feaA];
gnd = [ones(N,1);2*ones(N,1)];