frailty model for gap times

Hi there,

I have a question on the frailty model for gap times with distinct baseline 
hazard for each gap. Can I use R coxph function to do it? For example, the 
following code assumes an identical baseline hazard for every gap time, but 
what if I want a distinct baseline hazard for each gap?

coxph(Surv(gap,status)~trt+frailty(id))

Thanks in advance!




Lei Liu
Assistant Professor
Division of Biostatistics and Epidemiology
Dept. of Health Evaluation Sciences
School of Medicine
University of Virginia

3181 Hospital West Complex
Charlottesville, VA 22908-0717

1-434-982-3364 (o)
1-734-730-1395 (c)

liulei at virginia.edu
ll9f at virginia.edu