nlme (version 3.1-86)

pdDiag: Diagonal Positive-Definite Matrix

Description

This function is a constructor for the pdDiag class, representing a diagonal positive-definite matrix. If the matrix associated with object is of dimension $n$, it is represented by $n$ unrestricted parameters, given by the logarithm of the square-root of the diagonal values. When value is numeric(0), an uninitialized pdMat object, a one-sided formula, or a vector of character strings, object is returned as an uninitialized pdDiag object (with just some of its attributes and its class defined) and needs to have its coefficients assigned later, generally using the coef or matrix replacement functions. If value is an initialized pdMat object, object will be constructed from as.matrix(value). Finally, if value is a numeric vector, it is assumed to represent the unrestricted coefficients of the underlying positive-definite matrix.

Usage

pdDiag(value, form, nam, data)

Arguments

Value

a pdDiag object representing a diagonal positive-definite matrix, also inheriting from class pdMat.

References

Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer.

See Also

as.matrix.pdMat, coef.pdMat, pdClasses, matrix<-.pdMat

Examples

Run this code
pd1 <- pdDiag(diag(1:3), nam = c("A","B","C"))
pd1

Run the code above in your browser using DataCamp Workspace