debian man page for spstrf

spstrf.f(3)							      LAPACK							       spstrf.f(3)

NAME
       spstrf.f -

SYNOPSIS
   Functions/Subroutines
       subroutine spstrf (UPLO, N, A, LDA, PIV, RANK, TOL, WORK, INFO)
	   SPSTRF

Function/Subroutine Documentation
   subroutine spstrf (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA, integer, dimension( n )PIV, integerRANK, realTOL, real,
       dimension( 2*n )WORK, integerINFO)
       SPSTRF

       Purpose:

	    SPSTRF computes the Cholesky factorization with complete
	    pivoting of a real symmetric positive semidefinite matrix A.

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

	    This algorithm does not attempt to check that A is positive
	    semidefinite. This version of the algorithm calls level 3 BLAS.

       Parameters:
	   UPLO

		     UPLO is CHARACTER*1
		     Specifies whether the upper or lower triangular part of the
		     symmetric matrix A is stored.
		     = 'U':  Upper triangular
		     = 'L':  Lower triangular

	   N

		     N is INTEGER
		     The order of the matrix A.  N >= 0.

	   A

		     A is 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 as above.

	   LDA

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

	   PIV

		     PIV is INTEGER array, dimension (N)
		     PIV is such that the nonzero entries are P( PIV(K), K ) = 1.

	   RANK

		     RANK is INTEGER
		     The rank of A given by the number of steps the algorithm
		     completed.

	   TOL

		     TOL is REAL
		     User defined tolerance. If TOL < 0, then N*U*MAX( A(K,K) )
		     will be used. The algorithm terminates at the (K-1)st step
		     if the pivot <= TOL.

	   WORK

		     WORK is REAL array, dimension (2*N)
		     Work space.

	   INFO

		     INFO is INTEGER
		     < 0: If INFO = -K, the K-th argument had an illegal value,
		     = 0: algorithm completed successfully, and
		     > 0: the matrix A is either rank deficient with computed rank
			  as returned in RANK, or is indefinite.  See Section 7 of
			  LAPACK Working Note #161 for further information.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 141 of file spstrf.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.1							  Sun May 26 2013						       spstrf.f(3)