Contents
chpcon - estimate the reciprocal of the condition number of
a complex Hermitian packed matrix A using the factorization
A = U*D*U**H or A = L*D*L**H computed by CHPTRF
SUBROUTINE CHPCON(UPLO, N, A, IPIVOT, ANORM, RCOND, WORK, INFO)
CHARACTER * 1 UPLO
COMPLEX A(*), WORK(*)
INTEGER N, INFO
INTEGER IPIVOT(*)
REAL ANORM, RCOND
SUBROUTINE CHPCON_64(UPLO, N, A, IPIVOT, ANORM, RCOND, WORK, INFO)
CHARACTER * 1 UPLO
COMPLEX A(*), WORK(*)
INTEGER*8 N, INFO
INTEGER*8 IPIVOT(*)
REAL ANORM, RCOND
F95 INTERFACE
SUBROUTINE HPCON(UPLO, N, A, IPIVOT, ANORM, RCOND, [WORK], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: A, WORK
INTEGER :: N, INFO
INTEGER, DIMENSION(:) :: IPIVOT
REAL :: ANORM, RCOND
SUBROUTINE HPCON_64(UPLO, N, A, IPIVOT, ANORM, RCOND, [WORK], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: A, WORK
INTEGER(8) :: N, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
REAL :: ANORM, RCOND
C INTERFACE
#include <sunperf.h>
void chpcon(char uplo, int n, complex *a, int *ipivot, float
anorm, float *rcond, int *info);
void chpcon_64(char uplo, long n, complex *a, long *ipivot,
float anorm, float *rcond, long *info);
chpcon estimates the reciprocal of the condition number of a
complex Hermitian packed matrix A using the factorization A
= U*D*U**H or A = L*D*L**H computed by CHPTRF.
An estimate is obtained for norm(inv(A)), and the reciprocal
of the condition number is computed as RCOND = 1 / (ANORM *
norm(inv(A))).
UPLO (input)
Specifies whether the details of the factorization
are stored as an upper or lower triangular matrix.
= 'U': Upper triangular, form is A = U*D*U**H;
= 'L': Lower triangular, form is A = L*D*L**H.
N (input) The order of the matrix A. N >= 0.
A (input) The block diagonal matrix D and the multipliers
used to obtain the factor U or L as computed by
CHPTRF, stored as a packed triangular matrix.
IPIVOT (input)
Details of the interchanges and the block struc-
ture of D as determined by CHPTRF.
ANORM (input)
The 1-norm of the original matrix A.
RCOND (output)
The reciprocal of the condition number of the
matrix A, computed as RCOND = 1/(ANORM * AINVNM),
where AINVNM is an estimate of the 1-norm of
inv(A) computed in this routine.
WORK (workspace)
dimension(2*N)
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an ille-
gal value