rate_change {parTimeROC}

rate_change

Description

Function to compute the rate change of the ROC with respect to dx and dt.

Usage

rate_change(
  obj,
  t,
  n = 3,
  type = "standard",
  params.x,
  params.t,
  copula,
  definition = "c/d",
  params.copula,
  params.ph,
  seed,
  cutoff = 100,
  newx
)

Arguments

obj

A 'fitROC' or 'TimeROC' object.

t

A numeric/vector specifying the time of interest.

n

Number of point on the ROC curve which will be used to check the rate of change.

type

A string specifying the type of analysis used. (Default: 'standard')

params.x

A named vector for the biomarker's parameter.

params.t

A named vector for the time-to-event parameter.

copula

A string indicating the type of copula to be used.

definition

A string indicitaing the definition of ROC to use.

params.copula

A numeric for copula's parameter.

params.ph

A numeric for proportional hazard model's parameter.

seed

A numeric to pass in set.seed.

cutoff

A numeric to generate total biomarker used.

newx

A numeric.

Value

A list of rate change dt, dx and the angle between these rate of change.

Examples

## Using 'fitROC' object
test <- timeroc_obj("normal-weibull-copula", copula = "gaussian")
rr <- rtimeroc(test, n=500,
               params.x = c(mean=5, sd=0.8),
               params.t = c(shape=1.6, scale=5),
              params.copula = -0.3)
cc <- timeroc_fit(test, x = rr$x, t = rr$t, event = rr$event)
jj <- rate_change(cc, t = c(1,2,10,11))

## Using 'TimeROC' object
test <- timeroc_obj("normal-weibull-PH",
params.x = c(mean=5, sd=0.8),
params.t = c(shape=1.6, scale=5),
params.ph = 1)
ee <- rate_change(test, t = c(.1,.2))