function [xunit yunit] = circleposition(x,y,r,d)
%x and y are coordinates for the center and r = radius d= number of point
th = 0:pi/(d/2):2*pi;
th=th(1:end-1);
xunit = r * cos(th) + x;
yunit = r * sin(th) + y;
%  plot(xunit, yunit);

end