pim (version 2.0.2)

L: Specify the left hand and right hand side of an expression used in pims

Description

These functions allow you to specify the left hand side and right hand side of a term in a pim model. The user should only use this functions within a formula using the pim function. Use in a different context will return an error.

Usage

L(x)
R(x)
PP(x)

Arguments

x

any vector specified in a formula

Value

a vector with the pseudo-observations for x, based on the poset used to create the function. If used in a wrong context (i.e. not in a call to pim), it returns x unchanged and throws a warning.

warning

These functions serve only as placeholder. During the fitting process of a pim, they get updated to include the posets (the indices that determine which observations are compared) Note that this makes the functions behave fundamentally different from what you would expect R. The result of these functions depends on the context in which they are called.

Details

These specific functions are actually not used by the function pim. pim calls the internal function .make.posfun to create the actual functions L and R to work with the specified posets of the model of interest.

The actual functions used by pim are saved in a specific environment, a pim.environment, which resides in the pim-class object returned by pim. This way of working is chosen in order to avoid unnecessary copying of data.

The function PP serves simply as short for R(x) - L(x). If used outside the context of a pim model, it will generate multiple warnings (see section warning).

Examples

# NOT RUN {
pim(income~(L(foodexp) - R(foodexp)), data=Engeldata)
L(1:10) # Gives a warning
# }