ZTBCON(l)		LAPACK routine (version	1.1)		    ZTBCON(l)

NAME
  ZTBCON - estimate the	reciprocal of the condition number of a	triangular
  band matrix A, in either the 1-norm or the infinity-norm

SYNOPSIS

  SUBROUTINE ZTBCON( NORM, UPLO, DIAG, N, KD, AB, LDAB,	RCOND, WORK, RWORK,
		     INFO )

      CHARACTER	     DIAG, NORM, UPLO

      INTEGER	     INFO, KD, LDAB, N

      DOUBLE	     PRECISION RCOND

      DOUBLE	     PRECISION RWORK( *	)

      COMPLEX*16     AB( LDAB, * ), WORK( * )

PURPOSE
  ZTBCON estimates the reciprocal of the condition number of a triangular
  band matrix A, in either the 1-norm or the infinity-norm.

  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)) ).

ARGUMENTS

  NORM	  (input) CHARACTER*1
	  Specifies whether the	1-norm condition number	or the infinity-norm
	  condition number is required:
	  = '1'	or 'O':	 1-norm;
	  = 'I':	 Infinity-norm.

  UPLO	  (input) CHARACTER*1
	  = 'U':  A is upper triangular;
	  = 'L':  A is lower triangular.

  DIAG	  (input) CHARACTER*1
	  = 'N':  A is non-unit	triangular;
	  = 'U':  A is unit triangular.

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

  KD	  (input) INTEGER
	  The number of	superdiagonals or subdiagonals of the triangular band
	  matrix A.  KD	>= 0.

  AB	  (input) COMPLEX*16 array, dimension (LDAB,N)
	  The upper or lower triangular	band matrix A, stored in the first
	  kd+1 rows of the array. The j-th column of A is stored in the	j-th
	  column of the	array AB as follows: if	UPLO = 'U', AB(kd+1+i-j,j) =
	  A(i,j) for max(1,j-kd)<=i<=j;	if UPLO	= 'L', AB(1+i-j,j)    =
	  A(i,j) for j<=i<=min(n,j+kd).	 If DIAG = 'U',	the diagonal elements
	  of A are not referenced and are assumed to be	1.

  LDAB	  (input) INTEGER
	  The leading dimension	of the array AB.  LDAB >= KD+1.

  RCOND	  (output) DOUBLE PRECISION
	  The reciprocal of the	condition number of the	matrix A, computed as
	  RCOND	= 1/(norm(A) * norm(inv(A))).

  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