ZPOCON(l)		LAPACK routine (version	1.1)		    ZPOCON(l)

NAME
  ZPOCON - estimate the	reciprocal of the condition number (in the 1-norm) of
  a complex Hermitian positive definite	matrix using the Cholesky factoriza-
  tion A = U**H*U or A = L*L**H	computed by ZPOTRF

SYNOPSIS

  SUBROUTINE ZPOCON( UPLO, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO )

      CHARACTER	     UPLO

      INTEGER	     INFO, LDA,	N

      DOUBLE	     PRECISION ANORM, RCOND

      DOUBLE	     PRECISION RWORK( *	)

      COMPLEX*16     A(	LDA, * ), WORK(	* )

PURPOSE
  ZPOCON estimates the reciprocal of the condition number (in the 1-norm) of
  a complex Hermitian positive definite	matrix using the Cholesky factoriza-
  tion A = U**H*U or A = L*L**H	computed by ZPOTRF.

  An estimate is obtained for norm(inv(A)), and	the reciprocal of the condi-
  tion number is computed as RCOND = 1 / (ANORM	* norm(inv(A))).

ARGUMENTS

  UPLO	  (input) CHARACTER*1
	  = 'U':  Upper	triangle of A is stored;
	  = 'L':  Lower	triangle of A is stored.

  N	  (input) INTEGER
	  The order of the matrix A.  N	>= 0.

  A	  (input) COMPLEX*16 array, dimension (LDA,N)
	  The triangular factor	U or L from the	Cholesky factorization A =
	  U**H*U or A =	L*L**H,	as computed by ZPOTRF.

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

  ANORM	  (input) DOUBLE PRECISION
	  The 1-norm (or infinity-norm)	of the Hermitian 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 1-
	  norm of inv(A) computed in this routine.

  WORK	  (workspace) COMPLEX*16 array,	dimension (2*N)

  RWORK	  (workspace) DOUBLE PRECISION array, dimension	(N)

  INFO	  (output) INTEGER
	  = 0:	successful exit
	  < 0:	if INFO	= -i, the i-th argument	had an illegal value

Back to the listing of computational routines for linear equations