SPOTRF(l)		LAPACK routine (version	1.1)		    SPOTRF(l)

NAME
  SPOTRF - compute the Cholesky	factorization of a real	symmetric positive
  definite matrix A

SYNOPSIS

  SUBROUTINE SPOTRF( UPLO, N, A, LDA, INFO )

      CHARACTER	     UPLO

      INTEGER	     INFO, LDA,	N

      REAL	     A(	LDA, * )

PURPOSE
  SPOTRF computes the Cholesky factorization of	a real symmetric positive
  definite matrix A.

  The factorization has	the form
     A = U**T *	U,  if UPLO = 'U', or
     A = L  * L**T,  if	UPLO = 'L',
  where	U is an	upper triangular matrix	and L is lower triangular.

  This is the block version of the algorithm, calling Level 3 BLAS.

ARGUMENTS

  UPLO	  (input) CHARACTER*1
	  = 'U':  Upper	triangle of A is stored;
	  = 'L':  Lower	triangle of A is stored.

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

  A	  (input/output) REAL array, dimension (LDA,N)
	  On entry, the	symmetric matrix A.  If	UPLO = 'U', the	leading	N-
	  by-N upper triangular	part of	A contains the upper triangular	part
	  of the matrix	A, and the strictly lower triangular part of A is not
	  referenced.  If UPLO = 'L', the leading N-by-N lower triangular
	  part of A contains the lower triangular part of the matrix A,	and
	  the strictly upper triangular	part of	A is not referenced.

	  On exit, if INFO = 0,	the factor U or	L from the Cholesky factori-
	  zation A = U**T*U or A = L*L**T.

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

  INFO	  (output) INTEGER
	  = 0:	successful exit
	  < 0:	if INFO	= -i, the i-th argument	had an illegal value
	  > 0:	if INFO	= i, the leading minor of order	i is not positive
	  definite, and	the factorization could	not be completed.