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NAME
     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

SYNOPSIS
     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( * )



     #include <sunperf.h>

     void dgecon(char norm, int n, double *da,  int  lda,  double
               anorm, double *drcond, int *info) ;

PURPOSE
     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 ille-
               gal value

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