ergm.formula.utils: Internal Functions for Querying, Validating and Extracting from ERGM Formulas

Description

These are all functions that are generally not called directly by users, but may be employed by other depending packages.

Usage

ergm.getmodel(formula, nw, response = NULL, silent = FALSE, role = "static", ...)
ergm.getnetwork(form, loopswarning = TRUE)
ergm.getterms(formula)
offset.info.formula(object, response = NULL) 
remove.offset.formula(object, response = NULL)
# Deprecated. Use nonsimp.update.formula() from statnet.common package.
ergm.update.formula(object, new, ..., from.new = FALSE)

Arguments

formula

a formula of the form network ~ model.term(s)

the network of interest

response

charcter, name of edge attribute containing edge weights

silent

logical, whether to print the warning messages from the initialization of each model term; default=FALSE

role

A hint about how the model will be used. Used primarily for dynamic network models.

...

additional parameters for model formulation

form

same as formula, a formula of the form 'network ~ model.term(s)'

loopswarning

whether warnings about loops should be printed (T or F);default=TRUE

object

formula object to be updated

new

new formula to be used in updating

from.new

logical or character vector of variable names. controls how environment of formula gets updated.

Value

ergm.getmodel returns a 'model.ergm' object as a list containing:
- formula : the formula inputted toergm.getmodel
coef.names : a vector of coefficient names
offset : a logical vector of whether each term was "offset", i.e. fixed
terms : a list of terms and 'term components' initialized by the appropriate InitErgmTerm.X function.
network.stats0: NULL always??
etamap : the theta -> eta mapping as a list returned from
class : the character string "model.ergm"

code

remove.offset.formula

itemize

the terms object associated with the formula and returned by the native R functionterms>. seeterms.objectfor details about the components

Details

Theergm.getmodelfunction parses the given formula, and initiliazes each ergm term via theInitErgmTermfunctions to create amodel.ergmobject for the given network

The ergm.getnetwork function ensures that the network in a given formula is valid; if so, the network is returned; if not, execution is halted with warnings The ergm.getterms function returns the terms of a given formula and ensures that the formula is indeed a formula with the necessary ~ operator ergm.update.formula (DEPRECATED: use nonsimp.update.formula instead) is a reimplementation of update.formula that does not simplify. Note that the resulting formula's environment is set as follows. If from.new==FALSE, it is set to that of object. Otherwise, a new sub-environment of object, containing, in addition, variables in new listed in from.new (if a character vector) or all of new (if TRUE). offset.info.formula returns the offset vectors associated with a formula. remove.offset.formula deletes all offset terms in an ERGM formula.