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]]


