dpocon - estimate the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF
SUBROUTINE DPOCON( UPLO, N, A, LDA, ANORM, RCOND, WORK, WORK2, INFO) CHARACTER * 1 UPLO INTEGER N, LDA, INFO INTEGER WORK2(*) DOUBLE PRECISION ANORM, RCOND DOUBLE PRECISION A(LDA,*), WORK(*)
SUBROUTINE DPOCON_64( UPLO, N, A, LDA, ANORM, RCOND, WORK, WORK2, * INFO) CHARACTER * 1 UPLO INTEGER*8 N, LDA, INFO INTEGER*8 WORK2(*) DOUBLE PRECISION ANORM, RCOND DOUBLE PRECISION A(LDA,*), WORK(*)
SUBROUTINE POCON( UPLO, [N], A, [LDA], ANORM, RCOND, [WORK], [WORK2], * [INFO]) CHARACTER(LEN=1) :: UPLO INTEGER :: N, LDA, INFO INTEGER, DIMENSION(:) :: WORK2 REAL(8) :: ANORM, RCOND REAL(8), DIMENSION(:) :: WORK REAL(8), DIMENSION(:,:) :: A
SUBROUTINE POCON_64( UPLO, [N], A, [LDA], ANORM, RCOND, [WORK], * [WORK2], [INFO]) CHARACTER(LEN=1) :: UPLO INTEGER(8) :: N, LDA, INFO INTEGER(8), DIMENSION(:) :: WORK2 REAL(8) :: ANORM, RCOND REAL(8), DIMENSION(:) :: WORK REAL(8), DIMENSION(:,:) :: A
#include <sunperf.h>
void dpocon(char uplo, int n, double *a, int lda, double anorm, double *rcond, int *info);
void dpocon_64(char uplo, long n, double *a, long lda, double anorm, double *rcond, long *info);
dpocon estimates the reciprocal of the condition number (in the 1-norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF.
An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
inv(A)
computed in this routine.
dimension(3*N)
dimension(N)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value