survit function and cox model with frailty

I reassure you that you CAN get to the bottom of this.
I think you're making progress.  One step going forward
might be to look at  help("model.frame"), since that's
what causes the initial error message, and think about
how the arguments get matched in  survfit().

Actually I think one CAN'T get to the bottom of this.  I don't think
survfit works on models with frailties.

I don't actually understand what the intent is (and why the multiple time
periods with identical covariates), but it isn't going to be at all
straightforward to do a proper prediction for a single new case: the
survival curve should be the survival distribution with the frailty
integrated out, which is hard.

It should be possible to do a prediction setting the frailty to 1, but it
isn't.  Given that coxph will fit user-defined penalised likelihoods
survfit would have to be fairly clever to guess what it was supposed to do
in each circumstance.


	-thomas