ZGECON(3f)               LAPACK routine (version 3.1)               ZGECON(3f)



NAME
       ZGECON - the reciprocal of the condition number of a general complex
       matrix A, in either the 1-norm or the infinity-norm, using the LU
       factorization computed by ZGETRF

SYNOPSIS
       SUBROUTINE ZGECON( NORM, N, A, LDA, ANORM, RCOND, WORK, RWORK, INFO )

           CHARACTER      NORM

           INTEGER        INFO, LDA, N

           DOUBLE         PRECISION ANORM, RCOND

           DOUBLE         PRECISION RWORK( * )

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

PURPOSE
       ZGECON estimates the reciprocal of the condition number of a general
       complex matrix A, in either the 1-norm or the infinity-norm, using the
       LU factorization computed by ZGETRF.

       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) COMPLEX*16 array, dimension (LDA,N)
               The factors L and U from the factorization A = P*L*U as
               computed by ZGETRF.

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

       RWORK   (workspace) DOUBLE PRECISION array, dimension (2*N)

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



 LAPACK routine (version 3.1)    November 2006                      ZGECON(3f)
