rpart (version 3.1-9)

rpart.exp: Set up for `exp' Method for an Rpart Model

Description

Set up for the exp method for an rpart model.

Usage

rpart.exp(y, offset, parms, wt)

Arguments

y

the responses, a vector or a two-column matrix.

offset

an offset, or NULL.

parms

a list of parameters.

wt

case weights.

Value

• Returns a list consisting of
• y
  a matrix giving the observation times and number of events,
• parms
  a named list of parameters, with components shrink and method (1 for "deviance", 2 for "sqrt"),
• numresp
  the number of responses, here 2,
• numy
  the number of columns in y, here 2,
• summary
  a function to be invoked by summary.rpart,
• text
  a function to be invoked by text.rpart.

Details

rpart.exp is used only by the function rpart. It transforms the data to look like a unit-rate Poisson process so that the rpart.exp method can be used.