function xx = norminvcdf(uu, sigma, mu)
%NORMINVCDF Inverse Gaussian CDF without using the stats toolbox
%
%     xx = norminvcdf(uu, sigma, mu)

% Iain Murray, May 2009

if ~exist('sigma', 'var')
    sigma = 1;
end
if ~exist('mu', 'var')
    mu = 0;
end

xx = sqrt(2) * sigma * erfinv(2*uu - 1) + mu;