| pdMat {nlme} | R Documentation |
This function gives an alternative way of constructing an object
inheriting from the pdMat class named in pdClass, or
from data.class(object) if object inherits from
pdMat, and is mostly used internally in other functions. See
the documentation on the principal constructor function, generally
with the same name as the pdMat class of object.
pdMat(value, form, nam, data, pdClass)
value |
an optional initialization value, which can be any of the
following: a pdMat object, a positive-definite
matrix, a one-sided linear formula (with variables separated by
+), a vector of character strings, or a numeric
vector. Defaults to numeric(0), corresponding to an
uninitialized object. |
form |
an optional one-sided linear formula specifying the
row/column names for the matrix represented by object. Because
factors may be present in form, the formula needs to be
evaluated on a data.frame to resolve the names it defines. This
argument is ignored when value is a one-sided
formula. Defaults to NULL. |
nam |
an optional vector of character strings specifying the
row/column names for the matrix represented by object. It must have
length equal to the dimension of the underlying positive-definite
matrix and unreplicated elements. This argument is ignored when
value is a vector of character strings. Defaults to
NULL. |
data |
an optional data frame in which to evaluate the variables
named in value and form. It is used to
obtain the levels for factors, which affect the
dimensions and the row/column names of the underlying matrix. If
NULL, no attempt is made to obtain information on
factors appearing in the formulas. Defaults to the
parent frame from which the function was called. |
pdClass |
an optional character string naming the
pdMat class to be assigned to the returned object. This
argument will only be used when value is not a pdMat
object. Defaults to "pdSymm". |
a pdMat object representing a positive-definite matrix,
inheriting from the class named in pdClass, or from
class(object), if object inherits from pdMat.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer.
pdClasses,
pdCompSymm, pdDiag,
pdIdent, pdNatural,
pdSymm,
reStruct,
solve.pdMat,
summary.pdMat
pd1 <- pdMat(diag(1:4), pdClass = "pdDiag") pd1