------- begin included message -------- I'm trying to do some analysis using survreg function. I need to implement there my own distribution with density:
lambda*exp(-lambda*y), where y = a1/(1+exp(-a2*x)). a1, a2 are unknown parameters and x >0. --- end inclusion ------ The survreg function can fit location/scale families where the location parameter is Xb, X a matrix of predictors and b the parameters. I don't think that your distribution can be written in that form. An alternative is to take the apporach of the t-distribution for survreg, which has the right for for fixed df. Then wrap the survreg function inside optim, using the latter to get an estimate of df. No, I don't have time to give deeper programming help, due to other projects due. Terry Therneau ______________________________________________ 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.
