ergm (version 3.8.0)

san: Use Simulated Annealing to attempt to match a network to a vector of mean statistics

Description

This function attempts to find a network or networks whose statistics match those passed in via the target.stats vector.

Usage

# S3 method for formula
san(object, 
                      response=NULL, 
                      reference=~Bernoulli, 
                      constraints=~., 
                      target.stats=NULL,
                      nsim=1, 
                      basis=NULL,
                      sequential=TRUE,
                      control=control.san(),
                      verbose=FALSE, 
                      …)
# S3 method for ergm
san(object, 
                   formula=object$formula, 
                   constraints=object$constraints, 
                   target.stats=object$target.stats,
                   nsim=1, 
                   basis=NULL,
                   sequential=TRUE, 
                   control=object$control$SAN.control,
                   verbose=FALSE, 
                   …)

Arguments

object

Either a formula or an ergm object. The formula should be of the form y ~ <model terms>, where y is a network object or a matrix that can be coerced to a network object. For the details on the possible <model terms>, see ergm-terms. To create a network object in R, use the network() function, then add nodal attributes to it using the %v% operator if necessary.

response

EXPERIMENTAL. Name of the edge attribute whose value is to be modeled. Defaults to NULL for simple presence or absence.

reference

EXPERIMENTAL. One-sided formula whose RHS gives the reference measure to be used. (Defaults to ~Bernoulli.)

formula

(By default, the formula is taken from the ergm object. If a different formula object is wanted, specify it here.

constraints

A one-sided formula specifying one or more constraints on the support of the distribution of the networks being simulated. See the documentation for a similar argument for ergm and see list of implemented constraints for more information. For simulate.formula, defaults to no constraints. For simulate.ergm, defaults to using the same constraints as those with which object was fitted.

target.stats

A vector of the same length as the number of terms implied by the formula, which is either object itself in the case of san.formula or object$formula in the case of san.ergm.

nsim

Number of desired networks.

basis

If not NULL, a network object used to start the Markov chain. If NULL, this is taken to be the network named in the formula.

sequential

Logical: If TRUE, the returned draws always use the prior draw as the starting network; if FALSE, they always use the original network.

control

A list of control parameters for algorithm tuning; see control.san.

verbose

Logical: If TRUE, print out more detailed information as the simulation runs.

…

Further arguments passed to other functions.

Value

A network or list of networks that hopefully have network statistics close to the target.stats vector.