Chenge your model, most likely. You are telling us a) the response is discrete and b) there is a substantial probability that the value is zero. The gamma distributon is a model for a continuous response, your response is integer valued. Perhaps you should consider something the Poisson or Negative Binomial.
Evem from the little you give us, the problem seems more statistical than computational to me. Bill Venables CSIRO Laboratories PO Box 120, Cleveland, 4163 AUSTRALIA Office Phone (email preferred): +61 7 3826 7251 Fax (if absolutely necessary): +61 7 3826 7304 Mobile: +61 4 8819 4402 Home Phone: +61 7 3286 7700 mailto:[EMAIL PROTECTED] http://www.cmis.csiro.au/bill.venables/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Aswad Gurjar Sent: Sunday, 10 February 2008 4:17 PM To: r-help@r-project.org Subject: [R] Error in optim while using fitdistr() function for estimationof parameters Hello, I am trying to fit distribution for data consisting of 421 readings.It is basically no of requests arrived per minute.It contains many 0 entries as no of requests.When i use fd<-fitdistr(V2,"gamma") I get following error: Error in optim(x = c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, : initial value in 'vmmin' is not finite What should I do ? I need this function because I want to get value of estimated parameters. Is there any other function to perform such calculations? Please help me. Thank You. Code is as follows: x<-data.frame() N<-data.frame((read.table("cs2ip.txt"))) attach(N) library(MASS) fd<-fitdistr(V2,"gamma") Aswad [[alternative HTML version deleted]] ______________________________________________ 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. ______________________________________________ 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.
