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Computes the predicted survivor function for a phpe model.

Usage

# S3 method for phpe
survfit(formula, newdata, ...)

Arguments

formula

an object of the class phpe

newdata

a data frame containing the set of explanatory variables.

...

further arguments passed to or from other methods.

Value

a list containing the estimated survival probabilities.

Examples

# \donttest{
# ML approach:
library(YPPE)
mle <- phpe(Surv(time, status)~arm, data=ipass, n_int=10, approach="mle", init = 0)
summary(mle)
#> Call:
#> phpe(formula = Surv(time, status) ~ arm, data = ipass, n_int = 10, 
#>     approach = "mle", init = 0)
#> 
#> Proportional hazards coefficients:
#>      Estimate    StdErr z.value   p.value    
#> arm -0.310898  0.066011 -4.7098 2.479e-06 ***
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#> 
#> --- 
#> loglik = -2810.835   AIC = 5643.671 
ekm <- survival::survfit(Surv(time, status)~arm, data=ipass)
newdata <- data.frame(arm=0:1)
St <- survfit(mle, newdata)
plot(ekm, col=1:2)
with(St, lines(time, surv[[1]]))
with(St, lines(time, surv[[2]], col=2))


# Bayesian approach:
bayes <- phpe(Surv(time, status)~arm, data=ipass, n_int=10, approach="bayes")
#> 
#> SAMPLING FOR MODEL 'yppe' NOW (CHAIN 1).
#> Chain 1: 
#> Chain 1: Gradient evaluation took 0.000327 seconds
#> Chain 1: 1000 transitions using 10 leapfrog steps per transition would take 3.27 seconds.
#> Chain 1: Adjust your expectations accordingly!
#> Chain 1: 
#> Chain 1: 
#> Chain 1: Iteration:    1 / 2000 [  0%]  (Warmup)
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#> Chain 1: Iteration: 2000 / 2000 [100%]  (Sampling)
#> Chain 1: 
#> Chain 1:  Elapsed Time: 2.563 seconds (Warm-up)
#> Chain 1:                2.214 seconds (Sampling)
#> Chain 1:                4.777 seconds (Total)
#> Chain 1: 
#> 
#> SAMPLING FOR MODEL 'yppe' NOW (CHAIN 2).
#> Chain 2: 
#> Chain 2: Gradient evaluation took 0.00033 seconds
#> Chain 2: 1000 transitions using 10 leapfrog steps per transition would take 3.3 seconds.
#> Chain 2: Adjust your expectations accordingly!
#> Chain 2: 
#> Chain 2: 
#> Chain 2: Iteration:    1 / 2000 [  0%]  (Warmup)
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#> Chain 2: 
#> Chain 2:  Elapsed Time: 2.452 seconds (Warm-up)
#> Chain 2:                2.25 seconds (Sampling)
#> Chain 2:                4.702 seconds (Total)
#> Chain 2: 
#> 
#> SAMPLING FOR MODEL 'yppe' NOW (CHAIN 3).
#> Chain 3: 
#> Chain 3: Gradient evaluation took 0.00031 seconds
#> Chain 3: 1000 transitions using 10 leapfrog steps per transition would take 3.1 seconds.
#> Chain 3: Adjust your expectations accordingly!
#> Chain 3: 
#> Chain 3: 
#> Chain 3: Iteration:    1 / 2000 [  0%]  (Warmup)
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#> Chain 3: 
#> Chain 3:  Elapsed Time: 2.443 seconds (Warm-up)
#> Chain 3:                2.28 seconds (Sampling)
#> Chain 3:                4.723 seconds (Total)
#> Chain 3: 
#> 
#> SAMPLING FOR MODEL 'yppe' NOW (CHAIN 4).
#> Chain 4: 
#> Chain 4: Gradient evaluation took 0.000309 seconds
#> Chain 4: 1000 transitions using 10 leapfrog steps per transition would take 3.09 seconds.
#> Chain 4: Adjust your expectations accordingly!
#> Chain 4: 
#> Chain 4: 
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#> Chain 4: 
#> Chain 4:  Elapsed Time: 2.457 seconds (Warm-up)
#> Chain 4:                2.362 seconds (Sampling)
#> Chain 4:                4.819 seconds (Total)
#> Chain 4: 
summary(bayes)
#> Call:
#> phpe(formula = Surv(time, status) ~ arm, data = ipass, n_int = 10, 
#>     approach = "bayes")
#> 
#> Proportional hazards coefficients:
#>      mean se_mean    sd   2.5%    25%    50%    75%  97.5%    n_eff Rhat
#> arm -0.31   0.001 0.065 -0.439 -0.354 -0.311 -0.267 -0.183 3169.847    1
#> --- 
#> Inference for Stan model: yppe.
#> 4 chains, each with iter=2000; warmup=1000; thin=1; 
#> post-warmup draws per chain=1000, total post-warmup draws=4000.
#> 
ekm <- survival::survfit(Surv(time, status)~arm, data=ipass)
newdata <- data.frame(arm=0:1)
St <- survfit(bayes, newdata)
plot(ekm, col=1:2)
with(St, lines(time, surv[[1]]))
with(St, lines(time, surv[[2]], col=2))

# }