function npf=smooth(pf, n) 
%  smooth(pf, n)  Attempts to smooth out a probability density function. 
%     May be useful to salvage functions generated by getpf that don't turn 
%     out so good.  n is an optional parameter, specifying the number of 
%     interations to be done; 1 is the default. 
if ispf(pf)==0 
   error('not a valid probability function') 
end 
if isdiscrt(pf)==1 
   error('smooth is only for use with continuous functions') 
end 
if nargin==1 
   n=1; 
end 
if n>1 
   pf=smooth(pf, n-1); 
end 
x=xvals(pf); 
p=pvals(pf); 
np=zeros(size(p)); 
np(1)=p(1); 
for i=2:length(p), 
   np(i)=(p(i)+p(i-1))/2; 
end 
npf=[pf(1,:); x' np']; 
if ispf(npf)==0 
   np=np./ttlprob(npf); 
   npf=[pf(1,:); x' np']; 
end