SUBROUTINE CTPCON( NORM, UPLO, DIAG, N, A, RCOND, WORK, WORK2, INFO) CHARACTER * 1 NORM, UPLO, DIAG COMPLEX A(*), WORK(*) INTEGER N, INFO REAL RCOND REAL WORK2(*) SUBROUTINE CTPCON_64( NORM, UPLO, DIAG, N, A, RCOND, WORK, WORK2, * INFO) CHARACTER * 1 NORM, UPLO, DIAG COMPLEX A(*), WORK(*) INTEGER*8 N, INFO REAL RCOND REAL WORK2(*)
SUBROUTINE TPCON( NORM, UPLO, DIAG, N, A, RCOND, [WORK], [WORK2], * [INFO]) CHARACTER(LEN=1) :: NORM, UPLO, DIAG COMPLEX, DIMENSION(:) :: A, WORK INTEGER :: N, INFO REAL :: RCOND REAL, DIMENSION(:) :: WORK2 SUBROUTINE TPCON_64( NORM, UPLO, DIAG, N, A, RCOND, [WORK], [WORK2], * [INFO]) CHARACTER(LEN=1) :: NORM, UPLO, DIAG COMPLEX, DIMENSION(:) :: A, WORK INTEGER(8) :: N, INFO REAL :: RCOND REAL, DIMENSION(:) :: WORK2
void ctpcon(char norm, char uplo, char diag, int n, complex *a, float *rcond, int *info);
void ctpcon_64(char norm, char uplo, char diag, long n, complex *a, float *rcond, long *info);
The norm of A is computed and an estimate is obtained for norm(inv(A)), then the reciprocal of the condition number is computed as
RCOND = 1 / ( norm(A) * norm(inv(A)) ).