ssytrs2()

subroutine ssytrs2	(	character	uplo,
		integer	n,
		integer	nrhs,
		real, dimension( lda, * )	a,
		integer	lda,
		integer, dimension( * )	ipiv,
		real, dimension( ldb, * )	b,
		integer	ldb,
		real, dimension( * )	work,
		integer	info )

SSYTRS2

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Purpose:

!>
!> SSYTRS2 solves a system of linear equations A*X = B with a real
!> symmetric matrix A using the factorization A = U*D*U**T or
!> A = L*D*L**T computed by SSYTRF and converted by SSYCONV.
!> 

Parameters

[in]	UPLO	!> UPLO is 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. !>
[in]	N	!> N is INTEGER !> The order of the matrix A. N >= 0. !>
[in]	NRHS	!> NRHS is INTEGER !> The number of right hand sides, i.e., the number of columns !> of the matrix B. NRHS >= 0. !>
[in,out]	A	!> A is REAL array, dimension (LDA,N) !> The block diagonal matrix D and the multipliers used to !> obtain the factor U or L as computed by SSYTRF. !> Note that A is input / output. This might be counter-intuitive, !> and one may think that A is input only. A is input / output. This !> is because, at the start of the subroutine, we permute A in a !> form and then we permute A back to its original form at !> the end. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
[in]	IPIV	!> IPIV is INTEGER array, dimension (N) !> Details of the interchanges and the block structure of D !> as determined by SSYTRF. !>
[in,out]	B	!> B is REAL array, dimension (LDB,NRHS) !> On entry, the right hand side matrix B. !> On exit, the solution matrix X. !>
[in]	LDB	!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max(1,N). !>
[out]	WORK	!> WORK is REAL array, dimension (N) !>
[out]	INFO	!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.