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.