R: Internal Functions for Querying, Validating and Extracting...

ergm.formula.utils {ergm} | R Documentation

## 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)`
`nw` | 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.

### Details

- The `ergm.getmodel` function parses the given formula, and initiliazes each ergm term via the `InitErgmTerm` functions to create a `model.ergm` object 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.

### Value

`ergm.getmodel` returns a 'model.ergm' object as a list containing:

- formula : the formula inputted to `ergm.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 <ergm.etamap>

- class : the character string "model.ergm"

`ergm.getnetwork` returns:

- the network from the formula IF (i) the formula was correctly structured and (ii) the network is found within the formula's enviornment

`ergm.getterms` returns:

- the terms object associated with the formula and returned by the native R function `terms`>. see `terms.object` for details about the components

`terms.list.formula` returns a list of formula terms, each of witch having an additional attribute `"sign"`.

`ergm.update.formula`, `remove.offset.formula` and

[Package ergm version 3.8.0 Index]