Compute the determinant of A.
Return an estimate of the reciprocal condition number if requested.
Programming Notes: Routines from LAPACK are used for full matrices and code from UMFPACK is used for sparse matrices.
The determinant should not be used to check a matrix for singularity.
For that, use any of the condition number functions: cond,
condest, rcond.
See also: cond, condest, rcond.
Package: communications