SYTRS - 5.2 English - 68552

AOCL API Guide (68552)

Document ID
68552
Release Date
2025-12-29
Version
5.2 English
template<typename T>
void sytrs(char *uplo, integer *n, integer *nrhs, T *a, integer *lda, integer *ipiv, T *b, integer *ldb, integer *info)#

SYTRS solves a system of linear equations A*X = B with a real

symmetric matrix A.

Purpose:

  SYTRS 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 SYTRF.
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[in]

    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.

  • 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).

  • INFO[out]

    INFO is INTEGER

    = 0: successful exit

    < 0: if INFO = -i, the i-th argument had an illegal value