R Under development (unstable) (2024-06-02 r86665 ucrt) -- "Unsuffered Consequences"
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> options(na.action=na.exclude) # preserve missings
> options(contrasts=c('contr.treatment', 'contr.poly')) #ensure constrast type
> library(survival)
> 
> #
> # Verify that scale can be fixed at a value
> #    coefs will differ slightly due to different iteration paths
> tol <- .001
> 
> # Intercept only models
> fit1 <- survreg(Surv(time,status) ~ 1, lung)
> fit2 <- survreg(Surv(time,status) ~ 1, lung, scale=fit1$scale)
> all.equal(fit1$coef, fit2$coef, tolerance= tol)
[1] TRUE
> all.equal(fit1$loglik, fit2$loglik, tolerance= tol)
[1] TRUE
> 
> # The two robust variance matrices are not the same, since removing
> #   an obs has a different effect on the two models.  This just
> #   checks for failure, not for correctness
> fit3 <- survreg(Surv(time,status) ~ 1, lung, robust=TRUE)
> fit4 <- survreg(Surv(time,status) ~ 1, lung, scale=fit1$scale, robust=TRUE)
> 
> 
> # multiple covariates
> fit1 <- survreg(Surv(time,status) ~ age + ph.karno, lung)
> fit2 <- survreg(Surv(time,status) ~ age + ph.karno, lung,
+ 		scale=fit1$scale)
> all.equal(fit1$coef, fit2$coef, tolerance=tol)
[1] TRUE
> all.equal(fit1$loglik[2], fit2$loglik[2], tolerance=tol)
[1] TRUE
> 
> fit3 <- survreg(Surv(time,status) ~ age + ph.karno, lung, robust=TRUE)
> fit4 <- survreg(Surv(time,status) ~ age + ph.karno, lung, 
+                 scale=fit1$scale, robust=TRUE)
> 
> # penalized models
> fit1 <- survreg(Surv(time, status) ~ pspline(age), lung)
> fit2 <- survreg(Surv(time, status) ~ pspline(age), lung, scale=fit1$scale)
> all.equal(fit1$coef, fit2$coef, tolerance=tol)
[1] TRUE
> all.equal(fit1$loglik[2], fit2$loglik[2], tolerance=tol)
[1] TRUE
> 
> fit3 <- survreg(Surv(time,status) ~ pspline(age) + ph.karno, lung, robust=TRUE)
> fit4 <- survreg(Surv(time,status) ~ pspline(age) + ph.karno, lung, 
+                 scale=fit1$scale, robust=TRUE)
> 
> 
> 
> proc.time()
   user  system elapsed 
   0.85    0.07    0.90