R: Testing for curved exponential family

is.curved {ergm} | R Documentation

## Testing for curved exponential family

### Description

These functions test whether an ERGM fit, formula, or some other object represents a curved exponential family.

The method for `NULL` always returns `FALSE` by convention.

### Usage

    is.curved(object, ...)

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

    ## S3 method for class 'formula'
    is.curved(object, response = NULL, basis = NULL, ...)

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

### Arguments

`object` | An `ergm` object or an ERGM formula.
`...` | Arguments passed on to lower-level functions.
`response` | Either a character string, a formula, or `NULL` (the default), to specify the response attributes and whether the ERGM is binary or valued. Interpreted as follows: `NULL` Model simple presence or absence, via a binary ERGM. character string The name of the edge attribute whose value is to be modeled. Type of ERGM will be determined by whether the attribute is `logical` (`TRUE`/`FALSE`) for binary or `numeric` for valued. a formula must be of the form `NAME~EXPR|TYPE` (with `|` being literal). `EXPR` is evaluated in the formula's environment with the network's edge attributes accessible as variables. The optional `NAME` specifies the name of the edge attribute into which the results should be stored, with the default being a concise version of `EXPR`. Normally, the type of ERGM is determined by whether the result of evaluating `EXPR` is logical or numeric, but the optional `TYPE` can be used to override by specifying a scalar of the type involved (e.g., `TRUE` for binary and `1` for valued).
`basis` | See `ergm()`.

### Details

Curvature is checked by testing if all model parameters are canonical.

### Value

`TRUE` if the object represents a curved exponential family; `FALSE` otherwise.

[Package ergm version 4.2.1 Index]