This method function extracts sub-matrices from the positive-definite
matrix represented by x.
Usage
## S3 method for class 'pdMat':
[(x, i, j, drop = TRUE)
## S3 method for class 'pdMat':
[(x, i, j) <- value
Arguments
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.