dppfa
dppfa - (obsolete) compute a Cholesky factorization of a symmetric positive definite matrix
A in packed storage. It is typical to follow a call to SPPFA with a call to SPPSL to solve Ax = b or to SPPDI to
compute the determinant and inverse of A.
SUBROUTINE DPPFA( A, N, INFO)
INTEGER N, INFO
DOUBLE PRECISION A(*)
SUBROUTINE DPPFA_64( A, N, INFO)
INTEGER*8 N, INFO
DOUBLE PRECISION A(*)
#include <sunperf.h>
void dppfa(double *a, int n, int *info);
void dppfa_64(double *a, long n, long *info);
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* A (input/output)
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On entry, the upper triangle of the matrix A.
On exit, a Cholesky factorization of the matrix A.
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* N (input)
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Order of the matrix A. N >= 0.
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* INFO (output)
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On exit:
INFO = 0 Subroutine completed normally.
INFO > 0 Returns a value k if U(k,k) = 0 to indicate that SPPSL will divide by zero if called.