Hi there,
I was wondering whether you will be able to help me find the solution to the
following problem I am facing.
I am getting the following warning message when I was using the coxph in SPLUS
and I am not sure why and where it is happening. I have also printed my code
so you can see what I did to receive this warning.
I would really appreciate if any of you can find out the solution for me:-)
Regards,
Latha
Warning messages:
Ran out of iterations and did not converge in:
fitter(X, Y, strats, offset, init, control,
weights ....
>
Code I used:
> n<-30
> b<-2 #Cox regression parameter
> t<-0.106 #Value of t at which the function S(.) is studied
> x<-runif(n,0,1) # covariate value
> y<-1-exp(-t)^exp(b*x) #Survival time created from 1-(1-F(t))^exp(b*x)
> c<-runif(n,0,0.5)
> for (i in 1:n) ttt[i]<- min(y[i],c[i])
> for (j in 1:n) if (y[j]<=c[j]) delt[j]=1 else delt[j]=0
> data30106<-data.frame(x=x,ttt=ttt,delt=delt)
> data30106
x ttt delt
1 0.488711202 0.13562690 0
2 0.855828642 0.33931078 0
3 0.931598405 0.20061720 0
4 0.292845422 0.17337203 1
5 0.958126171 0.09910074 0
6 0.044562074 0.06945480 0
7 0.201170894 0.14658059 1
8 0.165116648 0.12390505 0
9 0.231906470 0.15511377 1
10 0.013588991 0.06923096 0
11 0.447032066 0.22831198 1
12 0.059958322 0.11264017 1
13 0.007346802 0.10198546 1
14 0.479377087 0.23039922 0
15 0.156308175 0.03428859 0
16 0.794690335 0.33846672 0
17 0.738001760 0.29515082 0
18 0.381364945 0.20329983 1
19 0.591780599 0.01012725 0
x ttt delt
20 0.765888012 0.38724433 0
21 0.445477461 0.12077320 0
22 0.028177253 0.02744334 0
23 0.908368614 0.07864741 0
24 0.647047109 0.23249965 0
25 0.142004033 0.05859883 0
26 0.452978511 0.09875219 0
27 0.342493692 0.18964039 1
28 0.444275566 0.22721162 1
29 0.971535333 0.14329526 0
30 0.519449620 0.05668219 0
> Surv(ttt,delt)
[1] 0.13562690+ 0.33931078+ 0.20061720+ 0.17337203
[5] 0.09910074+ 0.06945480+ 0.14658059 0.12390505+
[9] 0.15511377 0.06923096+ 0.22831198 0.11264017
[13] 0.10198546 0.23039922+ 0.03428859+ 0.33846672+
[17] 0.29515082+ 0.20329983 0.01012725+ 0.38724433+
[21] 0.12077320+ 0.02744334+ 0.07864741+ 0.23249965+
[25] 0.05859883+ 0.09875219+ 0.18964039 0.22721162
[29] 0.14329526+ 0.05668219+
> coxph(Surv(ttt,delt)~x)
Call:
coxph(formula = Surv(ttt, delt) ~ x)
coef exp(coef) se(coef) z p
x -355 6.1e-155 805 -0.441 0.66
Likelihood ratio test=43.9 on 1 df, p=3.53e-011 n=
30
Warning messages:
Ran out of iterations and did not converge in:
fitter(X, Y, strats, offset, init, control,
weights ....
>
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