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LAPACK version 3.0
dgecon(3)

PURPOSE
  DGECON - estimate the reciprocal of the condition number of a general real
  matrix A, in either the 1-norm or the infinity-norm, using the LU
  factorization computed by DGETRF

SYNTAX
  SUBROUTINE DGECON( NORM, N, A, LDA, ANORM, RCOND, WORK, IWORK, INFO )

      CHARACTER	     NORM

      INTEGER	     INFO, LDA, N

      DOUBLE	     PRECISION ANORM, RCOND

      INTEGER	     IWORK( * )

      DOUBLE	     PRECISION A( LDA, * ), WORK( * )

DESCRIPTION
  DGECON estimates the reciprocal of the condition number of a general real
  matrix A, in either the 1-norm or the infinity-norm, using the LU
  factorization computed by DGETRF.  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.

  A	  (input) DOUBLE PRECISION array, dimension (LDA,N)
	  The factors L and U from the factorization A = P*L*U as computed by
	  DGETRF.

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

  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, computed as
	  RCOND = 1/(norm(A) * norm(inv(A))).

  WORK	  (workspace) DOUBLE PRECISION array, dimension (4*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