| [.pdMat {nlme} | R Documentation |
This method function extracts sub-matrices from the positive-definite
matrix represented by x.
## S3 method for class 'pdMat': x[i, j, drop = TRUE] ## S3 method for class 'pdMat': x[i, j] <- value
x |
an object inheriting from class pdMat representing a
positive-definite matrix. |
i, j |
optional subscripts applying respectively to the rows
and columns of the positive-definite matrix represented by
object. When i (j) is omitted, all rows (columns)
are extracted. |
drop |
a logical value. If TRUE, single rows or columns are
converted to vectors. If FALSE the returned value retains its
matrix representation. |
value |
a vector, or matrix, with the replacement values for the
relevant piece of the matrix represented by x. |
if i and j are identical, the returned value will be
pdMat object with the same class as x. Otherwise, the
returned value will be a matrix. In the case a single row (or column)
is selected, the returned value may be converted to a vector,
according to the rules above.
Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates bates@stat.wisc.edu
pd1 <- pdSymm(diag(3)) pd1[1, , drop = FALSE] pd1[1:2, 1:2] <- 3 * diag(2)