zhecon (l)  Linux Man Pages
zhecon: estimates the reciprocal of the condition number of a complex Hermitian matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by ZHETRF
Command to display zhecon
manual in Linux: $ man l zhecon
NAME
ZHECON  estimates the reciprocal of the condition number of a complex Hermitian matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by ZHETRF
SYNOPSIS
 SUBROUTINE ZHECON(

UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK,
INFO )

CHARACTER
UPLO

INTEGER
INFO, LDA, N

DOUBLE
PRECISION ANORM, RCOND

INTEGER
IPIV( * )

COMPLEX*16
A( LDA, * ), WORK( * )
PURPOSE
ZHECON estimates the reciprocal of the condition number of a complex
Hermitian matrix A using the factorization A = U*D*U**H or
A = L*D*L**H computed by ZHETRF.
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) CHARACTER*1

Specifies whether the details of the factorization are stored
as an upper or lower triangular matrix.
= aqUaq: Upper triangular, form is A = U*D*U**H;
= aqLaq: Lower triangular, form is A = L*D*L**H.
 N (input) INTEGER

The order of the matrix A. N >= 0.
 A (input) COMPLEX*16 array, dimension (LDA,N)

The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by ZHETRF.
 LDA (input) INTEGER

The leading dimension of the array A. LDA >= max(1,N).
 IPIV (input) INTEGER array, dimension (N)

Details of the interchanges and the block structure of D
as determined by ZHETRF.
 ANORM (input) DOUBLE PRECISION

The 1norm of the original matrix A.
 RCOND (output) DOUBLE PRECISION

The reciprocal of the condition number of the matrix A,
computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an
estimate of the 1norm of inv(A) computed in this routine.
 WORK (workspace) COMPLEX*16 array, dimension (2*N)

 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
Pages related to zhecon
 zhecon (3)
 zheequb (l)  computes row and column scalings intended to equilibrate a symmetric matrix A and reduce its condition number (with respect to the twonorm)
 zheev (l)  computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 zheevd (l)  computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 zheevr (l)  computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 zheevx (l)  computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 zhegs2 (l)  reduces a complex Hermitiandefinite generalized eigenproblem to standard form
 zhegst (l)  reduces a complex Hermitiandefinite generalized eigenproblem to standard form