dspdi
dspdi - (obsolete) compute the determinant, inertia, and inverse of a symmetric matrix A in
packed storage, which has been UDU-factored by SSPCO or SSPFA.
SUBROUTINE DSPDI( A, N, IPIVOT, DET, INERT, WORK, JOB)
INTEGER N, JOB
INTEGER IPIVOT(*), INERT(*)
DOUBLE PRECISION A(*), DET(*), WORK(*)
SUBROUTINE DSPDI_64( A, N, IPIVOT, DET, INERT, WORK, JOB)
INTEGER*8 N, JOB
INTEGER*8 IPIVOT(*), INERT(*)
DOUBLE PRECISION A(*), DET(*), WORK(*)
#include <sunperf.h>
void dspdi(double *a, int n, int *ipivot, double *det, int *inert, int job);
void dspdi_64(double *a, long n, long *ipivot, double *det, long *inert, long job);
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* A (input/output)
-
On entry, the UDU factorization of the matrix A, as computed
by SSPCO or SSPFA. On exit, if the c digit of JOB <> 0, then A contains
the upper triangle of the inverse of the original matrix A; otherwise
unchanged.
-
* N (input)
-
Order of the original matrix A. N <> 0.
-
* IPIVOT (input)
-
Pivot vector as computed by SSPCO or SSPFA.
-
* DET (output)
-
On exit, if the b digit of JOB <> 0, then DET contains the
determinant of the matrix A. The determinant is stored as b * (10 ** expon)
where b is stored in DET(1) and expon is stored in DET(2).
1.0 <= |DET(1)| <= 10.0 or DET(1) = 0.0. If the b digit of JOB = 0, DET
is not referenced.
-
* INERT (output)
-
On exit, if the a digit of JOB <> 0 then INERT contains an integer triplet where:
INERT(1) = number of positive eigenvalues
INERT(2) = number of negative eigenvalues
INERT(3) = number of zero eigenvalues
If the a digit of JOB = 0 then INERT is not referenced.
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* WORK (workspace)
-
Scratch array with a dimension of N.
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* JOB (input)
-
Integer in the form abc; determines operation the subroutine will perform:
a <> 0 Compute the inertia.
b <> 0 Compute the determinant.
c <> 0 Compute the inverse.
Note that the inverse should not be computed if SSPCO has set RCOND = 0 or
if SSPFA has set INFO <> 0.