Good evening, folks:
I am trying to run a bootstrap on a CoxPH regression. I have set up a 1,000 x
1,000 matrix of "cases" and am running 1,000 analyses of 1,000 cases
each. The loop keeps breaking because of an error, and I have more or less
isolated the problem to a call of the coxph function with a subset of the cases.
Specifically, I am trying to regress a survival against poly(CREAT6MO,4).
I located one of the specific runs where the code was breaking and copied this
to "anomaly1". (Most of the runs work fine. About 1 in 20 seems to
fail.)
There are no missing or out of range values for TTFAIL, FFAIL, or CREAT6MO in
anomaly1.
poly(anomaly1$CREAT6MO,4) runs fine, with no error.
But -- coxph(Surv(TTFAIL - 182, FFAIL) ~ poly(CREAT6MO,4), data = anomaly1)
fails with the following error code.
Error in fitter(X, Y, strats, offset, init, control, weights = weights, :
NA/NaN/Inf in foreign function call (arg 6)
In addition: Warning message:
In fitter(X, Y, strats, offset, init, control, weights = weights, :
Ran out of iterations and did not converge
traceback() gives:
traceback()
3: .C("coxmart", as.integer(n), as.integer(method ==
"efron"), stime,
sstat, newstrat, as.double(score), as.double(weights), resid = double(n))
2: fitter(X, Y, strats, offset, init, control, weights = weights,
method = method, row.names(m))
1: coxph(Surv(TTFAIL - 182, FFAIL) ~ poly(CREAT6MO, 4), data = anomaly1)
This problem seems to be "above my payline." Any suggestions, anyone?
As always, many thanks in advance to any help that any of you can give me.
Larry Hunsicker