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
Although a future version of this package will include the
possibility to fit survival models, this is currently not implemented.
pim function encounters special functions on the
left-hand side (i.e. when
model won't be calculated.
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
are NOT copied to the
pim.formula. Also keep
in mind that the environment linked to the
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.
terms.object derived from the formula
a logical value indicating whether the right-hand
side of the original formula contains special functions like
a logical value indicating whether the left-hand
side of the original formula contains special functions. These
exclude the functions
include functions like
Surv. See Details
a character vector with the names of all the variables mentioned in the right-hand side of the formula.
an character vector with the name of the response variable.
a call with the processed left-hand side of the formula
a formula object with the original formula
environment object to which the
formula is related (i.e. the environment containing possible
R function definitions.) See Details.
a logical value indicating whether the formula has an explicit intercept (indicated by + 1)
This class is not exported, so it can't be extended as for now.
Although it is possible to use the function
creation of new instances, users are strongly advised to use
new.pim.formula in case they need to manually
create a new instance of the class