function y=npdf(t,mu,sigma)

% NPDF        Normal probability density function.
%
%             Examples: npdf(0)
%                       npdf(0,1,2)  
% 
%             NPDF(T,MU,SIGMA) calculates the normal pdf at T. 
%             If MU (mean) and SIGMA (sd) are omitted, values of 
%             0 and 1 are assumed.
%
%             Christian C. Beardah 1995

if nargin==1,
  sigma=1;
  mu=0;
end;

y=knorm((t-mu)/sigma)/sigma;