SUBROUTINE CGECON( NORM, N, A, LDA, ANORM, RCOND, WORK, WORK2, INFO) CHARACTER * 1 NORM COMPLEX A(LDA,*), WORK(*) INTEGER N, LDA, INFO REAL ANORM, RCOND REAL WORK2(*) SUBROUTINE CGECON_64( NORM, N, A, LDA, ANORM, RCOND, WORK, WORK2, * INFO) CHARACTER * 1 NORM COMPLEX A(LDA,*), WORK(*) INTEGER*8 N, LDA, INFO REAL ANORM, RCOND REAL WORK2(*)
SUBROUTINE GECON( NORM, [N], A, [LDA], ANORM, RCOND, [WORK], [WORK2], * [INFO]) CHARACTER(LEN=1) :: NORM COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A INTEGER :: N, LDA, INFO REAL :: ANORM, RCOND REAL, DIMENSION(:) :: WORK2 SUBROUTINE GECON_64( NORM, [N], A, [LDA], ANORM, RCOND, [WORK], * [WORK2], [INFO]) CHARACTER(LEN=1) :: NORM COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A INTEGER(8) :: N, LDA, INFO REAL :: ANORM, RCOND REAL, DIMENSION(:) :: WORK2
void cgecon(char norm, int n, complex *a, int lda, float anorm, float *rcond, int *info);
void cgecon_64(char norm, long n, complex *a, long lda, float anorm, float *rcond, long *info);
An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as
RCOND = 1 / ( norm(A) * norm(inv(A)) ).