DGETRI(l)		LAPACK routine (version	1.1)		    DGETRI(l)

NAME
  DGETRI - compute the inverse of a matrix using the LU	factorization com-
  puted	by DGETRF

SYNOPSIS

  SUBROUTINE DGETRI( N,	A, LDA,	IPIV, WORK, LWORK, INFO	)

      INTEGER	     INFO, LDA,	LWORK, N

      INTEGER	     IPIV( * )

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

PURPOSE
  DGETRI computes the inverse of a matrix using	the LU factorization computed
  by DGETRF.

  This method inverts U	and then computes inv(A) by solving the	system
  inv(A)*L = inv(U) for	inv(A).

ARGUMENTS

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

  A	  (input/output) DOUBLE	PRECISION array, dimension (LDA,N)
	  On entry, the	factors	L and U	from the factorization A = P*L*U as
	  computed by DGETRF.  On exit,	if INFO	= 0, the inverse of the	ori-
	  ginal	matrix A.

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

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

  WORK	  (workspace) DOUBLE PRECISION array, dimension	(LWORK)
	  On exit, if INFO=0, then WORK(1) returns the optimal LWORK.

  LWORK	  (input) INTEGER
	  The dimension	of the array WORK.  LWORK >= max(1,N).	For optimal
	  performance LWORK >= N*NB, where NB is the optimal blocksize
	  returned by ILAENV.

  INFO	  (output) INTEGER
	  = 0:	successful exit
	  < 0:	if INFO	= -i, the i-th argument	had an illegal value
	  > 0:	if INFO	= i, U(i,i) is exactly zero; the matrix	is singular
	  and its inverse could	not be computed.