function pmf=mfpoiss(lamda) 
% mfpoiss(lamda)  generates a Poisson pmd with parameter lamda 
if(lamda<=0) 
   error('invalid value for lamda') 
end 
X=10; 
while ((lamda^X)*exp(-lamda)/fact(X)) > 1e-6 
   X=X+1; 
end 
x=[0:X]; 
p=zeros(1, X+1); 
for i=1:X+1, 
   p(i)=exp(-lamda)*(lamda^x(i))./fact(x(i)); 
end 
pmf=[1 1; x' p'];