cspfa
cspfa - (obsolete) compute the UDU factorization of a symmetric matrix A in packed
storage. It is typical to follow a call to CSPFA with a call to
CSPSL to solve Ax = b or to CSPDI to compute the
determinant, inverse, and inertia of A.
SUBROUTINE CSPFA( A, N, IPIVOT, INFO)
COMPLEX A(*)
INTEGER N, INFO
INTEGER IPIVOT(*)
SUBROUTINE CSPFA_64( A, N, IPIVOT, INFO)
COMPLEX A(*)
INTEGER*8 N, INFO
INTEGER*8 IPIVOT(*)
#include <sunperf.h>
void cspfa(complex *a, int n, int *ipivot, int *info);
void cspfa_64(complex *a, long n, long *ipivot, long *info);
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* A (input/output)
-
On entry, the upper triangle of the matrix A.
On exit, a UDU factorization of the matrix A.
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* N (input)
-
Order of the matrix A. N >= 0.
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* IPIVOT (output)
-
On exit, a vector of pivot indices.
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* INFO (output)
-
On exit:
INFO = 0 Subroutine completed normally.
INFO > 0 Returns a value k if the kth pivot block is
singular to indicate that CSPSL or CSPDI will divide by zero if called.