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 `reStruct` ,
representing a random effects structure and consisting of a list of
`pdMat` objects. |

### 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)

Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu

### See Also

`pdMatrix.reStruct`

, `pdFactor.pdMat`

### Examples

rs1 <- reStruct(pdSymm(diag(3), ~age+Sex, data = Orthodont))
pdFactor(rs1)

[Package

*nlme* version 3.1-57

Index]