Hi,
I have been using maxLik to do some MLE of Geometric Brownian Motion Process and everything has been going fine, but know I have tried to do it with jumps. I have create a vector of jumps and then added this into my log-likelihood equation, know I am getting a message: NA in the initial gradient My codes is hear # n<-length(combinedlr) j<-c(1,2,3,4,5,6,7,8,9,10) gbmploglik<-function(param){ mu<-param[1] sigma<-param[2] lamda<-param[3] nu<-param[4] gama<-param[5] logLikVal<- - n*lamda - .5*n*log(2*pi) + sum(log(sum(for(j in 1:10)(cat((lamda^j/factorial(j))*(1/((sigma^2+j*gama^2)^.5)*exp( - (combinedlr-mu-j*nu)^2/2*(sigma^2+j*gama^2)))))))) logLikVal } rescbj<- maxLik(gbmploglik, grad = NULL, hess = NULL, start=c(0,1,1,1,1), method = "Newton-Raphson") summary(rescbj) # I am also was wondering if anyone know if there was a package that dealt with Geometric Brownian Motion Process augmented with jumps. Then I could just put that into my code and might resolve the issue. Any suggest as to how to resolved this issue, are greatly apprecaited. Yours truly, JP ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.