Determinant of a Matrix from LU Decomposition

DESCRIPTION:
Computes the determinant (or its logarithm) of a Matrix from its LU decomposition.

USAGE:
det.lu.Matrix(x, logarithm=T)

REQUIRED ARGUMENTS:
x:
an object of class "lu.Matrix" representing the LU decomposition of a square Matrix.

OPTIONAL ARGUMENTS:
logarithm:
a logical variable indicating whether or not the logarithm of the modulus of the determinant should be returned rather than the determinant itself. The default is to return the logarithm.

VALUE:
returns an object of class "det".

DETAILS:
The determinant is computed from a triangular factorization obtained via the function dgetrf or zgetrf from LAPACK (Anderson et al. 1994).

REFERENCES:
Anderson, E., et al. (1994). LAPACK User's Guide, 2nd edition, SIAM, Philadelphia. Golub, G., and Van Loan, C. F. (1989). Matrix Computations, 2nd edition, Johns Hopkins, Baltimore.

SEE ALSO:
det.object , det.Matrix .

EXAMPLES:
x <- Matrix( sample(-3:3, size = 9, replace = T), nrow = 3, ncol = 3)
det(lu(x))