[R] exponential proportional hazard model

[Daniel Gutknecht]

Dear R-users,

I am looking for a function designed to handle parametric proportional hazard models with a piecewise constant baseline hazard (i.e. dummies for annual intervals) and time-dependent covariates since I'm especially interested about the effect of those covariates on the baseline hazard.
I tried survreg() but this doesn't seem to work since my data looks like this

id/ start/ stop/ censoring/ covariates  
 1/   0/     5/     0/      ...
 1/   5/     8/     1/
 2/   0/     4/     0/

and survreg(Surv(start,stop,censoring)~covariates,...) always returns 'invalid survival type' (specifying the type="right" returns "wrong number of args...").
Am I missing something or is there a function that can handle this kind of data.
Thanks
Daniel   
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