| pdFactor.reStruct {nlme} | R Documentation |
This method function extracts square-root factors of the
positive-definite matrices corresponding to the pdMat elements
of object.
## S3 method for class 'reStruct': pdFactor(object)
object |
an object inheriting from class reStruct,
representing a random effects structure and consisting of a list of
pdMat objects. |
a vector with square-root factors of the positive-definite matrices
corresponding to the elements of object stacked column-wise.
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.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
pdMatrix.reStruct, pdFactor.pdMat
rs1 <- reStruct(pdSymm(diag(3), ~age+Sex, data = Orthodont)) pdFactor(rs1)