function y = circularRandCardioid(d)
%
%< circularRandCardioid >
%  Returns random value of Cardioid distribution.
%
%  rand('state',sum(100*clock));  % reset rand() function.
%  rand(2);
%  a = circularRandCardioid([2,3])
%
%  Unit is radian.
%

warning('circularRandCardioid has not been implemented. Sorry... :)');
y=nan;
return;