function w=gausspdf(x,sigma)
% gausspdf - Gaussian probability density
%
% gausspdf :: [Size->real] -> [Size->nonneg].
% gausspdf :: [Size->real], nonneg ~'stddev of Guassian' -> [Size->nonneg].
% 	returns normal (gaussian) pdf of 1st argument. 

if nargin<2, sigma=1; end;
w=exp(-0.5*(x./sigma).^2)./(sigma*sqrt(2*pi));
