LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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◆ dsytrs_aa()

subroutine dsytrs_aa ( character uplo,
integer n,
integer nrhs,
double precision, dimension( lda, * ) a,
integer lda,
integer, dimension( * ) ipiv,
double precision, dimension( ldb, * ) b,
integer ldb,
double precision, dimension( * ) work,
integer lwork,
integer info )

DSYTRS_AA

Download DSYTRS_AA + dependencies [TGZ] [ZIP] [TXT]

Purpose:
!>
!> DSYTRS_AA solves a system of linear equations A*X = B with a real
!> symmetric matrix A using the factorization A = U**T*T*U or
!> A = L*T*L**T computed by DSYTRF_AA.
!>
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**T*T*U;
!>          = 'L':  Lower triangular, form is A = L*T*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]A
!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          Details of factors computed by DSYTRF_AA.
!>
[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 as computed by DSYTRF_AA.
!>
[in,out]B
!>          B is DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (MAX(1,LWORK))
!>
[in]LWORK
!>          LWORK is INTEGER
!>          The dimension of the array WORK.
!>          If MIN(N,NRHS) = 0, LWORK >= 1, else LWORK >= 3*N-2.
!>
!>          If LWORK = -1, then a workspace query is assumed; the routine
!>          only calculates the minimal size of the WORK array, returns
!>          this value as the first entry of the WORK array, and no error
!>          message related to LWORK is issued by XERBLA.
!>
[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.