pim.formula-class {pim}

Class pim.formula

Description

This class contains information on the formula passed in a call to pim. The object is used to create the model matrix of a pim (see model.matrix)

Details

Although a future version of this package will include the possibility to fit survival models, this is currently not implemented. If the pim function encounters special functions on the left-hand side (i.e. when has.lhs.fun is TRUE), the model won't be calculated.

The slot penv contains a reference to an environment In most cases, this will be the environment contained in a pim.environment object. Note though that the pim.formula object only contains a link to the environment. The extra slots contained in the pim.environment object are NOT copied to the pim.formula. Also keep in mind that the environment linked to the pim.environment object will continue to exist even after deleting the pim.environment itself, and this for as long as the pim.formula object exists.

This class is not exported and hence cannot be extended. It serves internal use in the pim package only.

Slots

terms

a terms.object derived from the formula

has.specials

a logical value indicating whether the right-hand side of the original formula contains special functions like L and R

has.lhs.fun

a logical value indicating whether the left-hand side of the original formula contains special functions. These exclude the functions P and PO but include functions like Surv. See Details

predictors

a character vector with the names of all the variables mentioned in the right-hand side of the formula.

response

an character vector with the name of the response variable.

lhs

a call with the processed left-hand side of the formula

orig

a formula object with the original formula

penv

an environment object to which the formula is related (i.e. the environment containing possible L and R function definitions.) See Details.

has.intercept

a logical value indicating whether the formula has an explicit intercept (indicated by + 1)

Note

This class is not exported, so it can't be extended as for now. Although it is possible to use the function new for creation of new instances, users are strongly advised to use the function new.pim.formula in case they need to manually create a new instance of the class pim.formula.