spocon - 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 SPOCON( UPLO, N, A, LDA, ANORM, RCOND, WORK, WORK2, INFO) CHARACTER * 1 UPLO INTEGER N, LDA, INFO INTEGER WORK2(*) REAL ANORM, RCOND REAL A(LDA,*), WORK(*)
SUBROUTINE SPOCON_64( UPLO, N, A, LDA, ANORM, RCOND, WORK, WORK2, * INFO) CHARACTER * 1 UPLO INTEGER*8 N, LDA, INFO INTEGER*8 WORK2(*) REAL ANORM, RCOND REAL 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 :: ANORM, RCOND REAL, DIMENSION(:) :: WORK REAL, 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 :: ANORM, RCOND REAL, DIMENSION(:) :: WORK REAL, DIMENSION(:,:) :: A
#include <sunperf.h>
void spocon(char uplo, int n, float *a, int lda, float anorm, float *rcond, int *info);
void spocon_64(char uplo, long n, float *a, long lda, float anorm, float *rcond, long *info);
spocon 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