| pdFactor.reStruct {nlme} | R Documentation |
Extract Square-Root Factor from Components of an reStruct Object
Description
This method function extracts square-root factors of the
positive-definite matrices corresponding to the pdMat elements
of object.
Usage
## S3 method for class 'reStruct'
pdFactor(object)
Arguments
object |
an object inheriting from class |
Value
a vector with square-root factors of the positive-definite matrices
corresponding to the elements of object stacked column-wise.
Note
This function is used intensively in optimization
algorithms and its value is returned as a vector for efficiency
reasons. The pdMatrix function can be used to obtain
square-root factors in matrix form.
Author(s)
José Pinheiro and Douglas Bates bates@stat.wisc.edu
References
Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer.
See Also
pdFactor,
pdMatrix.reStruct,
pdFactor.pdMat
Examples
rs1 <- reStruct(pdSymm(diag(3), ~age+Sex, data = Orthodont))
pdFactor(rs1)