zppcon(3P) Sun Performance Library zppcon(3P)NAMEzppcon - estimate the reciprocal of the condition number (in the
1-norm) of a complex Hermitian positive definite packed matrix using
the Cholesky factorization A = U**H*U or A = L*L**H computed by ZPPTRF
SYNOPSIS
SUBROUTINE ZPPCON(UPLO, N, A, ANORM, RCOND, WORK, WORK2, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX A(*), WORK(*)
INTEGER N, INFO
DOUBLE PRECISION ANORM, RCOND
DOUBLE PRECISION WORK2(*)
SUBROUTINE ZPPCON_64(UPLO, N, A, ANORM, RCOND, WORK, WORK2, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX A(*), WORK(*)
INTEGER*8 N, INFO
DOUBLE PRECISION ANORM, RCOND
DOUBLE PRECISION WORK2(*)
F95 INTERFACE
SUBROUTINE PPCON(UPLO, [N], A, ANORM, RCOND, [WORK], [WORK2], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: A, WORK
INTEGER :: N, INFO
REAL(8) :: ANORM, RCOND
REAL(8), DIMENSION(:) :: WORK2
SUBROUTINE PPCON_64(UPLO, [N], A, ANORM, RCOND, [WORK], [WORK2], [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: A, WORK
INTEGER(8) :: N, INFO
REAL(8) :: ANORM, RCOND
REAL(8), DIMENSION(:) :: WORK2
C INTERFACE
#include <sunperf.h>
void zppcon(char uplo, int n, doublecomplex *a, double anorm, double
*rcond, int *info);
void zppcon_64(char uplo, long n, doublecomplex *a, double anorm, dou‐
ble *rcond, long *info);
PURPOSEzppcon estimates the reciprocal of the condition number (in the 1-norm)
of a complex Hermitian positive definite packed matrix using the
Cholesky factorization A = U**H*U or A = L*L**H computed by ZPPTRF.
An estimate is obtained for norm(inv(A)), and the reciprocal of the
condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
ARGUMENTS
UPLO (input)
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N (input) The order of the matrix A. N >= 0.
A (input) COMPLEX*16 array, dimension (N*(N+1)/2)
The triangular factor U or L from the Cholesky factorization
A = U**H*U or A = L*L**H, packed columnwise in a linear
array. The j-th column of U or L is stored in the array A as
follows: if UPLO = 'U', A(i + (j-1)*j/2) = U(i,j) for
1<=i<=j; if UPLO = 'L', A(i + (j-1)*(2n-j)/2) = L(i,j) for
j<=i<=n.
ANORM (input)
The 1-norm (or infinity-norm) of the Hermitian matrix A.
RCOND (output)
The reciprocal of the condition number of the matrix A, com‐
puted as RCOND = 1/(ANORM * AINVNM), where AINVNM is an esti‐
mate of the 1-norm of inv(A) computed in this routine.
WORK (workspace)
COMPLEX*16 array, dimension(2*N)
WORK2 (workspace)
DOUBLE PRECISION array, dimension(N)
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
6 Mar 2009 zppcon(3P)
