function y = log_pnorm(x,mu,sigma)

%%log_pnorm(x,mu,sigma) returns the log of the probability of observing x from a normal distribution with
%%mean mu and variance exp(sigma)

temp1 = -(0.5)*log(2*pi) - (0.5)*log(sigma);
%temp2 = log(sigma) - log(2) + 2*log(x) + 2*log(1-(mu/x));

if x~=mu 
    temp2 = -log(sigma) - log(2) +log((x-mu)^2);
    y= temp1 - exp(temp2);
else
    y=temp1;
end