Hi, I need help to write the following log-likelihood function in R: log(L) = sum [(y_k - y_k-1).log(m(t_k) - m(t_k-1)) - (m(t_k) - m(t_k-1)) - log((y_k -y_k-1)!)] I need to write this log-likelihood function in order to find the parameters by MLE method. Appreciate the help. -- View this message in context: http://www.nabble.com/How-to-write-the-log-function-in-R-tp19264137p19264137.html Sent from the R help mailing list archive at Nabble.com.
toh <tohbin <at> yahoo.com> writes:> > > Hi, > > I need help to write the following log-likelihood function in R: > log(L) = sum [(y_k - y_k-1).log(m(t_k) - m(t_k-1)) - (m(t_k) - m(t_k-1)) - > log((y_k -y_k-1)!)] > > I need to write this log-likelihood function in order to find the parameters > by MLE method. >if you have a vector y_k then diff(y_k) should give you a vector corresponding to (y_k - y_k-1) [I assume you mean y_{k-1} rather than {y_k}-1 above!] log(x!) is lfactorial(x) in R sum() works as expected the rest should be pretty easy ... Ben Bolker