This is a method for the generic function valid
for spatial logistic regression models (class "slrm").
In a model fitted by slrm, some of the fitted
coefficients may be NA or infinite values.
This can occur if the data are not
adequate for estimation of the model parameters. The model is said
to be unidentifiable or confounded.
The function valid.slrm checks whether the fitted coefficients of
object specify a well-defined model. It returns
TRUE if the model is well-defined, and FALSE otherwise.
Use the function emend.slrm to force the fitted model
to be valid.