Displaying 7 results from an estimated 7 matches for "coxfit".
2001 Feb 22
3
[newbie] Cox Baseline Hazard
Hello everybody.
First of all, I would like to present myself.
I'm a french student in public health and I like statistics though I'm
not that good in mathematics (but I try to catch up). I've discovered R
recently while trying to find a statistical program in order to avoid
rebooting my computer under windows when I need to do some statistical
work.
And here is my first question.
2004 Aug 13
1
How to use the whole dataset (including between events) in Cox model (time-varying covariates) ?
...mated parameters.
Any ideas ???
.
.
.
A second best (which might require less work) would be to use all the
dataset to assess the predictive power of the model.
Maybe by using the expected number of events for an individual over the
time interval that they were observed to be at risk
> predict(coxfit,type="expected")
and compare it with observed number of events
(does it use all data and takes into account all the baseline hazard, even
between events?)
Or, if not, following Brian D. Ripley suggestion about the baseline
hazard: "As an approximation you can smooth the fitted
bas...
2007 Dec 17
2
Capture warning messages from coxph()
Hi,
I want to fit multiple cox models using the coxph() function. To do
this, I use a for-loop and save the relevant results in a separate
matrix. In the example below, only two models are fitted (my actual
matrix has many more columns), one gives a warning message, while the
other does not. Right now, I see all the warning message(s) after the
for-loop is completed but have no idea which model
2004 Dec 16
0
fitting problems in coxph.fit
...fail to estimate
the regression coefficients when some values of the design matrix are very
large. For example
library(survival)
### load example data
load(url("http://www.imbe.med.uni-erlangen.de/~hothorn/coxph_fit.Rda"))
method <- "efron"
### copied from `coxph.fit'
coxfit <- .C("coxfit2", iter=as.integer(maxiter),
as.integer(n),
as.integer(nvar), stime,
sstat,
x= x[sorted,] ,
as.double(offset[sorted] - mean(offset)),
as.double(weights),...
2006 Mar 08
2
Survival Plots by Strata
...e.g., min(Entry for each year)) is where each
curve begins at S_hat=1 for each year (and does not extend back to the
y-axis)? I could not find anything on this in the archives or MASS or
Survival Analysis using S? Anyone have a suggestion on where to look?
TIA, Bret
#Code snip for R email.
apc.coxfit1<-coxph(Surv(Entry, Exit, Fate)~Sex + Agerelease +
Dayrelease + strata(Year), data=mydat)
coxfit.apc<-survfit(apc.coxfit1)
coxfit.apc
plot(survfit(apc.coxfit1), conf.int=F, log=T, lty=c(1:2), col=c(1:2),
xlim=c(205, 800)) #not run--first entry for this example is day 205 for
1996, 259 for 199...
2011 Oct 03
2
number of copies
I'm looking at memory efficiency for some of the survival code. The
following fragment appears in coxph.fit
coxfit <- .C("coxfit2", iter=as.integer(maxiter),
as.integer(n),
as.integer(nvar), stime,
sstat,
x= x[sorted,] ,
...
Does this make a second copy of x to pass to the routine (my
expectation) or will I end up w...
2004 Nov 17
1
frailty and time-dependent covariate
...A_FIN1)+D1500+D3000+D4500+frailty.gaussian(ID),data=SURV1)
Warning messages:
1: Inner loop failed to coverge for iterations 1 3 in: coxpenal.fit(X, Y, strats, offset, init = init, control, weights = weights,
2: longer object length
is not a multiple of shorter object length in: offset + coxfit$fcoef[x[, fcol]]
3: X matrix deemed to be singular; variable 8 in: coxph(Surv(DATA_INI1, DATA_FIN1, EVENT1) ~ V1 + V2 + alt1 + alt2 +
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