DSYTRI(l)		LAPACK routine (version	1.1)		    DSYTRI(l)

NAME
  DSYTRI - compute the inverse of a real symmetric indefinite matrix A using
  the factorization A =	U*D*U**T or A =	L*D*L**T computed by DSYTRF

SYNOPSIS

  SUBROUTINE DSYTRI( UPLO, N, A, LDA, IPIV, WORK, INFO )

      CHARACTER	     UPLO

      INTEGER	     INFO, LDA,	N

      INTEGER	     IPIV( * )

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

PURPOSE
  DSYTRI computes the inverse of a real	symmetric indefinite matrix A using
  the factorization A =	U*D*U**T or A =	L*D*L**T computed by DSYTRF.

ARGUMENTS

  UPLO	  (input) CHARACTER*1
	  Specifies whether the	details	of the factorization are stored	as an
	  upper	or lower triangular matrix.  = 'U':  Upper triangular, form
	  is A = U*D*U**T;
	  = 'L':  Lower	triangular, form is A =	L*D*L**T.

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

  A	  (input/output) DOUBLE	PRECISION array, dimension (LDA,N)
	  On entry, the	block diagonal matrix D	and the	multipliers used to
	  obtain the factor U or L as computed by DSYTRF.

	  On exit, if INFO = 0,	the (symmetric)	inverse	of the original
	  matrix.  If UPLO = 'U', the upper triangular part of the inverse is
	  formed and the part of A below the diagonal is not referenced; if
	  UPLO = 'L' the lower triangular part of the inverse is formed	and
	  the part of A	above the diagonal is not referenced.

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

  IPIV	  (input) INTEGER array, dimension (N)
	  Details of the interchanges and the block structure of D as deter-
	  mined	by DSYTRF.

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

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