sposv(l) [redhat man page]

SPOSV(l)								 )								  SPOSV(l)

NAME

       SPOSV - compute the solution to a real system of linear equations A * X = B,

SYNOPSIS

       SUBROUTINE SPOSV( UPLO, N, NRHS, A, LDA, B, LDB, INFO )

	   CHARACTER	 UPLO

	   INTEGER	 INFO, LDA, LDB, N, NRHS

	   REAL 	 A( LDA, * ), B( LDB, * )

PURPOSE

       SPOSV  computes	the solution to a real system of linear equations A * X = B, where A is an N-by-N symmetric positive definite matrix and X
       and B are N-by-NRHS matrices.

       The Cholesky decomposition is used to factor A as
	  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 a lower triangular matrix.  The factored form of A is then used to solve the system of equa-
       tions A * X = B.

ARGUMENTS

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

       N       (input) INTEGER
	       The number of linear equations, i.e., the order of the matrix A.  N >= 0.

       NRHS    (input) INTEGER
	       The number of right hand sides, i.e., the number of columns of the matrix B.  NRHS >= 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).

       B       (input/output) REAL array, dimension (LDB,NRHS)
	       On entry, the N-by-NRHS right hand side matrix B.  On exit, if INFO = 0, the N-by-NRHS solution matrix X.

       LDB     (input) INTEGER
	       The leading dimension of the array B.  LDB >= 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 of A is not positive definite, so the factorization could not be completed, and the
	       solution has not been computed.

LAPACK version 3.0						   15 June 2000 							  SPOSV(l)

sposv.f(3)							      LAPACK								sposv.f(3)

NAME

       sposv.f -

SYNOPSIS

   Functions/Subroutines
       subroutine sposv (UPLO, N, NRHS, A, LDA, B, LDB, INFO)
	    SPOSV computes the solution to system of linear equations A * X = B for PO matrices

Function/Subroutine Documentation
   subroutine sposv (characterUPLO, integerN, integerNRHS, real, dimension( lda, * )A, integerLDA, real, dimension( ldb, * )B, integerLDB,
       integerINFO)
	SPOSV computes the solution to system of linear equations A * X = B for PO matrices

       Purpose:

	    SPOSV computes the solution to a real system of linear equations
	       A * X = B,
	    where A is an N-by-N symmetric positive definite matrix and X and B
	    are N-by-NRHS matrices.

	    The Cholesky decomposition is used to factor A as
	       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 a lower triangular
	    matrix.  The factored form of A is then used to solve the system of
	    equations A * X = B.

       Parameters:
	   UPLO

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

	   N

		     N is INTEGER
		     The number of linear equations, i.e., the order of the
		     matrix A.	N >= 0.

	   NRHS

		     NRHS is INTEGER
		     The number of right hand sides, i.e., the number of columns
		     of the matrix B.  NRHS >= 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 A = U**T*U or A = L*L**T.

	   LDA

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

	   B

		     B is REAL array, dimension (LDB,NRHS)
		     On entry, the N-by-NRHS right hand side matrix B.
		     On exit, if INFO = 0, the N-by-NRHS solution matrix X.

	   LDB

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

	   INFO

		     INFO is 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 of A is not
			   positive definite, so the factorization could not be
			   completed, and the solution has not been computed.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 131 of file sposv.f.

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

Version 3.4.2							  Tue Sep 25 2012							sposv.f(3)