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LAPACK version 3.0
spotrf(3)

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

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

      CHARACTER	     UPLO

      INTEGER	     INFO, LDA, N

      REAL	     A( LDA, * )

DESCRIPTION
  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
	  factorization 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.