enformulate.curved {ergm} | R Documentation |
The generic enformulate.curved
converts an ergm
object or
formula of a model with curved terms to the variant in which the curved
parameters embedded into the formula and are removed from the parameter
vector. This is the form required by ergm
calls.
## S3 method for class 'ergm' enformulate.curved(object, ...) ## S3 method for class 'formula' enformulate.curved(object, theta, ...)
object |
An |
theta |
Curved model parameter configuration. |
... |
Unused at this time. |
Because of a current kludge in ergm
, output from one
run cannot be directly passed as initial values (theta0
) for
the next run if any of the terms are curved. One workaround is to
embed the curved parameters into the formula (while keeping
fixed=FALSE
) and remove them from theta0
.
This function automates this process for curved ERGM terms included
with the ergm
package. It does not work with curved terms not
included in ergm.
A list with the following components:
formula |
The formula with curved parameter estimates incorporated. |
theta |
The coefficient vector with curved parameter estimates removed. |
data(sampson) gest<-ergm(samplike~edges+gwesp(alpha=.5,fixed=FALSE),maxit=1) # Error: gest2<-try(ergm(gest$formula,theta0=coef(gest),maxit=2)) print(gest2) # Works: tmp<-enformulate.curved(gest) tmp gest2<-try(ergm(tmp$formula,theta0=tmp$theta,maxit=2)) summary(gest2)