R: Internal representation of an 'ergm' network model

ergm_model {ergm} | R Documentation

## Internal representation of an `ergm` network model

### Description

These methods are generally not called directly by users, but may be employed by other depending packages. `ergm_model` constructs it from a formula. Each term is initialized via the `InitErgmTerm` functions to create a `ergm_model` object.

### Usage

    ergm_model(
      formula,
      nw = NULL,
      silent = FALSE,
      ...,
      term.options = list(),
      extra.aux = list(),
      env = globalenv(),
      offset.decorate = TRUE
    )

    ## S3 method for class 'ergm_model'
    c(...)

    as.ergm_model(x, ...)

    ## S3 method for class 'ergm_model'
    as.ergm_model(x, ...)

    ## S3 method for class 'formula'
    as.ergm_model(x, ...)

    ## S3 method for class 'ergm_model'
    is.curved(object, ...)

    ## S3 method for class 'ergm_model'
    is.dyad.independent(object, ...)

    ## S3 method for class 'ergm_model'
    nparam(object, canonical = FALSE, offset = NA, byterm = FALSE, ...)

    ## S3 method for class 'ergm_model'
    param_names(object, canonical = FALSE, offset = NA, ...)

### Arguments

`formula` | An `ergm()` formula of the form `network ~ model.term(s)` or `~ model.term(s)`.
`nw` | The network of interest; if passed, the LHS of `formula` is ignored. This is the recommended usage.
`silent` | logical, whether to print the warning messages from the initialization of each model term.
`...` | additional parameters for model formulation
`term.options` | A list of additional arguments to be passed to term initializers. See `? term.options`.
`extra.aux` | a list of auxiliary request formulas required elsewhere; if named, the resulting `slots.extra.aux` will also be named.
`env` | a throwaway argument needed to prevent conflicts with some usages of `ergm_model`. The initialization environment is always taken from the `formula`.
`offset.decorate` | logical; whether offset coefficient and parameter names should be enclosed in `"offset()"`.
`x` | object to be converted to an `ergm_model`.
`object` | An `ergm_model` object.
`canonical` | Whether the canonical (eta) parameters or the curved (theta) parameters are used.
`offset` | If `NA` (the default), all model terms are counted; if `TRUE`, only offset terms are counted; and if `FALSE`, offset terms are skipped.
`byterm` | Whether to return a vector of the numbers of coefficients for each term.

### Value

`ergm_model` returns an `ergm_model` object as a list containing:

`terms` | a list of terms and 'term components' initialized by the appropriate `InitErgmTerm.X` function.
`etamap` | the theta -> eta mapping as a list returned from <ergm.etamap>

### Methods (by generic)

- `c`: A method for concatenating terms of two or more initialized models.

- `is.curved`: Tests whether the model is curved.

- `is.dyad.independent`: Tests whether the model is dyad-independent.

- `nparam`: Number of parameters of the model.

- `param_names`: Parameter names of the model.

### Note

This API is not to be considered fixed and may change between versions. However, an effort will be made to ensure that the methods of this class remain stable.

### See Also

`summary.ergm_model()`

[Package ergm version 4.2.1 Index]