?sytrs

Solves a system of linear equations A * X = B with a symmetric matrix.

call ssytrs_aa(uplo, n, nrhs, A, lda, ipiv, B, ldb, work, lwork, info)

call dsytrs_aa(uplo, n, nrhs, A, lda, ipiv, B, ldb, work, lwork, info)

call csytrs_aa(uplo, n, nrhs, A, lda, ipiv, B, ldb, work, lwork, info)

call zsytrs_aa(uplo, n, nrhs, A, lda, ipiv, B, ldb, work, lwork, info)

Description

?sytrs_aa solves a system of linear equations A * X = B with a symmetric matrix A using the factorization A = U*T*U^T or A = L*T*L^T computed by ?sytrf_aa.

Input Parameters

uplo

CHARACTER*1

Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.

= 'U': Upper triangular; the form is A = U*T*U^T.
= 'L': Lower triangular; the form is A = L*T*L^T.

n

INTEGER

The order of the matrix A. n ≥ 0.

nrhs

INTEGER

The number of right-hand sides; that is, the number of columns of the matrix B. nrhs ≥ 0.

A

REAL for ssytrs_aa

DOUBLE COMPLEX for dsytrs_aa

COMPLEX for csytrs_aa

COMPLEX*16 for zsytrs_aa

Array, dimension (lda,n). Details of factors computed by ?sytrf_aa.

lda

INTEGER

The leading dimension of the array A.lda ≥ max(1, n).

ipiv

INTEGER

Array, dimension (n). Details of the interchanges as computed by ?sytrf_aa.

B

REAL for ssytrs_aa

DOUBLE COMPLEX for dsytrs_aa

COMPLEX for csytrs_aa

COMPLEX*16 for zsytrs_aa

Array, dimension (ldb,nrhs). On entry, the right-hand side matrix B.

ldb

INTEGER

The leading dimension of the array B. ldb ≥ max(1, n).

work

Array, dimension (MAX(1,lwork)).

REAL for ssytrs_aa

DOUBLE COMPLEX for dsytrs_aa

COMPLEX for csytrs_aa

COMPLEX*16 for zsytrs_aa

lwork

INTEGER

The length of the array work.

Output Parameters

B

REAL for ssytrs_aa

DOUBLE COMPLEX for dsytrs_aa

COMPLEX for csytrs_aa

COMPLEX*16 for zsytrs_aa

On exit, the solution matrix X.

info

INTEGER

If info = 0: Successful exit.
< 0: If info = -i, the i^th argument had an illegal value.