function y = F(x)
%
% F is the cdf of the random variable X in the Lloyd-Max Algorithm
%
% F(x) = int_{-\infty}^x p(t) d t.
%
% y = (1+erf(x/sqrt(2)))/2; % y = normcdf(x)
lambda = .85;
m = 4;
sigma = .5;
y = lambda * normcdf(x) + (1-lambda)*normcdf(x,m,sigma);
