function y = cpoisson(mu,k)
% CPOISSON y = cpoisson(mu,k) Cumulative Poisson probabilities
% Version of 10/15/93
% mu = mean value mu 
% k may be a row or column vector of integer values
% y = P(X >= k) (a row vector of probabilities)
K = max(k);
p = exp(-mu)*cumprod([1 mu*ones(1,K)]./[1 1:K]);
pc = [1 1 - cumsum(p)];
y = pc(k+1);