PS. 11 MILLION entries?? On Tue, 30 Sep 2003, Ben Bolker wrote:
> > Spencer Graves's suggestion of using shape and scale parameters on a log > scale is a good one. > > To do specifically what you want (check values for which the objective > function is called and see what happens) you can do the following > (untested!), which makes a local copy of dgamma that you can mess with: > > dgamma.old <- dgamma > dgamma <- function(x,shape,rate,...) { > d <- dgamma.old(x,shape,rate,...) > cat(shape,rate,d,"\n") > return(d) > } > > > On Tue, 30 Sep 2003, Lourens Olivier Walters wrote: > > > Dear R Users, > > > > I am trying to obtain a best-fit analytic distribution for a dataset > > with 11535459 entries. The data range in value from 1 to 300000000. I > > use: fitdistr(data, "gamma") to obtain mle's for the parameters. > > > > I get the following error: > > > > Error in optim(start, mylogfn, x = x, hessian = TRUE, ...) : > > non-finite finite-difference value [1] > > > > And the following warnings: > > > > NaNs produced in: dgamma(x, shape, scale, log) > > > > I have the same problem with the exponential distribution, but the > > lognormal and weibull distributions don't have this problem. > > > > I suspect the problem has to do with: > > > > "It means that in computing derivatives by finite differencing, one > > of the values is NA, +Inf or -Inf. Put some print values in > > your objective function and find out why it is giving a non-finite > > value." - quote by Prof Ripley from r-help > > > > as from the warnings it is clear that some of the values obtained during > > maximum likelihood computations are NaN. I cannot however print values > > of the objective function, as in my case it is dgamma which is called by > > fitdistr, over which I don't have control. > > > > Can anyone please point me in the right direction? > > > > Lourens > > > > > > -- 620B Bartram Hall [EMAIL PROTECTED] Zoology Department, University of Florida http://www.zoo.ufl.edu/bolker Box 118525 (ph) 352-392-5697 Gainesville, FL 32611-8525 (fax) 352-392-3704 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help