Hello Lucy, If you carefully read, it is is not an error message, but a warning message. It tells you that for the moment, if I am not mistaken, "pphsm" does not return the correct covariance matrix, for any fitting.
Regards, Pascal On Thu, Apr 3, 2014 at 11:29 AM, Lucy Leigh <lucy.le...@newcastle.edu.au> wrote: > Hi everyone, > I am attempting to use the R package 'rms' > http://biostat.mc.vanderbilt.edu/wiki/Main/Rrms > to implement a PH weibull model, using the pphsm() function. > > However, I get the following error, > f.ph <- pphsm(f) > Warning message: > In pphsm(f) : > at present, pphsm does not return the correct covariance matrix > > I tried simply running the example on page 117 of the manual, i.e. > set.seed(1) > S <- Surv(runif(100)) > x <- runif(100) > dd <- datadist(x); options(datadist='dd') > f <- psm(S ~ x, dist="exponential") > summary(f) # effects on log(T) scale > f.ph <- pphsm(f) > ## Not run: summary(f.ph) > > But I still got the above error message. > I have looked through the R help archives, and it appears that this question > has been asked before in 2011, but > there were no replies. > http://r.789695.n4.nabble.com/HELP-td3494640.html > > Does anyone know how to get this function to work? Or if there is an > alternative package that can implement > a Weibull PH model? > Cheers, > Lucy > > [[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. -- Pascal Oettli Project Scientist JAMSTEC Yokohama, Japan ______________________________________________ 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.