Subscript a pdMat Object

DESCRIPTION:

This method function extracts sub-matrices from the positive-definite matrix represented by x.

USAGE:

x[i, j, drop] 
x[i, j] <- value 

REQUIRED ARGUMENTS:

x
an object inheriting from class pdMat representing a positive-definite matrix.

OPTIONAL ARGUMENTS:

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.

VALUE:

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.

SEE ALSO:

, .

EXAMPLES:

pd1 <- pdSymm(diag(3)) 
pd1[1, , drop = F] 
pd1[1:2, 1:2] <- 3 * diag(2)