Hello, I am going to estimate the parameter of the count model: pr(N=n)= integration{B(x, alpha)-C(x,alpha)} by maximum likelihood estimation.? n<-c(0,1,2,3) ? and ? F<- (0,3,4,5) are the vectors of values and observed frequency respectively. The function C(x,alpha) is not defined for n=0, but suppose C(x,alpha)=1 when n=0. ?When I want to insert this exception in the following loop, I don't receive reasonable estimate. pari (alpha){ nloglik<- function(alpha){ B<-function(x,k){........} C<-function(x,k){........} A<-function(x){ s<-rep(0,length(x)) s<-s+ C(x,k)? s<- s+B(x,k)? } s } d<-0 for (n in seq(along=F)){ ?lik<-integrate(A,0,1)$value d<- d - F[n]*log(lik)}} d?} F<-??(0,3,4,5) n<-length(F) mle (nloglik, start=list(alpha=alpha) } ? ?? This program gives the answer when n= 1,2,3. But for n=0 I get error, I have to consider the exception :?C(x,alpha)=1. ? Does anybody know where I need to put the exception in the program? ( For 'if' loops, I don't get reasonable results)? I would appreciate any help Best Regards,?? ?? ?