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template<typename T>
void sytrs2(char *uplo, integer *n, integer *nrhs, T *a, integer *lda, integer *ipiv, T *b, integer *ldb, T *work, integer *info)# SYTRS2 solves a system of linear equations A*X = B with a real
symmetric matrix A.
Purpose:
SYTRS2 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:
UPLO – [in]
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.
N – [in]
N is INTEGER
The order of the matrix A. N >= 0.
NRHS – [in]
NRHS is INTEGER
The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
A – [inout]
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 “better” form and then we permute A back to its original form at the end.
LDA – [in]
LDA is INTEGER
The leading dimension of the array A. LDA >= fla_max(1,N).
IPIV – [in]
IPIV is INTEGER array, dimension (N)
Details of the interchanges and the block structure of D as determined by SSYTRF.
B – [inout]
B is REAL array, dimension (LDB,NRHS)
On entry, the right hand side matrix B. On exit, the solution matrix X.
LDB – [in]
LDB is INTEGER
The leading dimension of the array B. LDB >= fla_max(1,N).
WORK – [out] WORK is REAL array, dimension (N)
INFO – [out]
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value