HP MLIB User's Guide Vol. 2 7th Ed.

Chapter 13 Sparse Linear Equations 897
Numeric factorization DSLEFA
INTEGER*8 inrtia(3), ier
REAL*8 pvttol
REAL*8 global(150)
CALL DSLEFA(pvttol, inrtia, global, ier)
INTEGER*8 inrtia(3), ier
REAL*16 pvttol
REAL*8 global(150)
CALL QSLEFA(pvttol, inrtia, global, ier)
INTEGER*8 inrtia(3), ier
COMPLEX*8 pvttol
REAL*8 global(150)
CALL CSLEFA(pvttol, inrtia, global, ier)
INTEGER*8 inrtia(3), ier
COMPLEX*16 pvttol
REAL*8 global(150)
CALL ZSLEFA(pvttol, inrtia, global, ier)
Input pvttol Pivoting tolerance; 0 ≤ pvttol ≤ 1. The value 0 gives a
reordering that minimizes fill; this value is appropriate
for positive definite matrices and provides the greatest
efficiency. The value 1 gives the best guarantee of
numerical stability for problems not known to be
positive definite.
pvttol is not used in the unsymmetric case.
Updated global Global communications array for this problem. This
array must be passed, untouched by the user, to
successive subroutines in this package.
Output inrtia Array of length 3 containing, respectively, the number
of positive eigenvalues, the number of negative
eigenvalues, and an indicator if there are zero
eigenvalues.
ier Status response:
ier = 0 Normal return.
ier = −500 Incorrect processing path; value
input not performed.
ier = −501 Error in dynamic storage allocation
during factorization.