A cormat method extracts the x slot of an object of
"parameter.cormat". A coef method extracts the
x slot of an object that inherits from "parameter.coef".
There is no special extractor function for objects of "parameter.scale".
There are also show methods. The most important methods are those defined for the make_parameter
S4 generic. This function takes two arguments, "par", which is a
numeric vector but not part of the signature, and "object", which
is an object that inherits from the "parameter" class. The
make_parameter methods are defined for each inherited class and
basically do two things. First, they do something like this
object@x[object@free] <- par[object@select]
to fill the free elements of x with corresponding values from
"par". Then, these methods often check whether the parameters
are collectively admissable under the assumptions of the factor analysis
model. If not, the make_parameter method must set the
invalid slot to some number that is greater than $-1.0$ and not
$0.0$. It is preferable if larger values somehow indicate more flagrant
inadmissability, since this number is used as a return value in the
lexical optimization process (see genoud). Finally,
the make_parameter should return object.