This method function converts
object to a
pdBandNat
object, represented in a natural parameterization. If
unconstrained = TRUE
, an unconstrained parameterization based
on the logarithm of the standard deviations and the logit of the
correlations (log((1+r)/(1-r)), with
r denoting the correlation) is used. If
unconstrained
is set to
FALSE, the variances and
covariances are used to parameterize the returned
pdBandNat
object.
USAGE:
asNatural(object, unconstrained)
REQUIRED ARGUMENTS:
object
an object inheriting from class
pdBand,
representing a banded positive-definite matrix, whose
representation is to be converted to a natural parameterization.
OPTIONAL ARGUMENTS:
unconstrained
an optional logical value indicating whether the
natural parameterization should be unconstrained. Defaults to
TRUE.
VALUE:
an object of class
pdBandNat representing a banded
positive-definite matrix in natural parameterization.
SEE ALSO:
,
,
EXAMPLES:
pd1 <- pdBand(diag(1:3), form = ~age + age^2, data = Orthodont)
asNatural(pd1)