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DGBCON(1)		 LAPACK routine (version 3.2)		     DGBCON(1)

NAME
       DGBCON  -  estimates  the  reciprocal of the condition number of a real
       general band matrix A, in either the 1-norm or the infinity-norm,

SYNOPSIS
       SUBROUTINE DGBCON( NORM, N, KL, KU, AB, LDAB, IPIV, ANORM, RCOND, WORK,
			  IWORK, INFO )

	   CHARACTER	  NORM

	   INTEGER	  INFO, KL, KU, LDAB, N

	   DOUBLE	  PRECISION ANORM, RCOND

	   INTEGER	  IPIV( * ), IWORK( * )

	   DOUBLE	  PRECISION AB( LDAB, * ), WORK( * )

PURPOSE
       DGBCON  estimates the reciprocal of the condition number of a real gen‐
       eral band matrix A, in either the 1-norm or  the	 infinity-norm,	 using
       the LU factorization computed by DGBTRF.
       An  estimate  is	 obtained  for norm(inv(A)), and 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.

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

       KL      (input) INTEGER
	       The number of subdiagonals within the band of A.	 KL >= 0.

       KU      (input) INTEGER
	       The number of superdiagonals within the band of A.  KU >= 0.

       AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
	       Details	of  the LU factorization of the band matrix A, as com‐
	       puted by DGBTRF.	 U is  stored  as  an  upper  triangular  band
	       matrix  with KL+KU superdiagonals in rows 1 to KL+KU+1, and the
	       multipliers used during the factorization are  stored  in  rows
	       KL+KU+2 to 2*KL+KU+1.

       LDAB    (input) INTEGER
	       The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.

       IPIV    (input) INTEGER array, dimension (N)
	       The  pivot  indices;  for  1 <= i <= N, row i of the matrix was
	       interchanged with row IPIV(i).

       ANORM   (input) DOUBLE PRECISION
	       If NORM = '1' or 'O', the 1-norm of the original matrix A.   If
	       NORM = 'I', the infinity-norm of the original matrix A.

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

       WORK    (workspace) DOUBLE PRECISION array, dimension (3*N)

       IWORK   (workspace) INTEGER array, dimension (N)

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

 LAPACK routine (version 3.2)	 November 2008			     DGBCON(1)
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