DSYTRS(3)      LAPACK routine of NEC Numeric Library Collection      DSYTRS(3)



NAME
       DSYTRS

SYNOPSIS
       SUBROUTINE DSYTRS (UPLO, N, NRHS, A, LDA, IPIV, B, LDB, INFO)



PURPOSE
            DSYTRS 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 DSYTRF.




ARGUMENTS
           UPLO      (input)
                     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         (input)
                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           NRHS      (input)
                     NRHS is INTEGER
                     The number of right hand sides, i.e., the number of columns
                     of the matrix B.  NRHS >= 0.

           A         (input)
                     A is DOUBLE PRECISION array, dimension (LDA,N)
                     The block diagonal matrix D and the multipliers used to
                     obtain the factor U or L as computed by DSYTRF.

           LDA       (input)
                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(1,N).

           IPIV      (input)
                     IPIV is INTEGER array, dimension (N)
                     Details of the interchanges and the block structure of D
                     as determined by DSYTRF.

           B         (input/output)
                     B is DOUBLE PRECISION array, dimension (LDB,NRHS)
                     On entry, the right hand side matrix B.
                     On exit, the solution matrix X.

           LDB       (input)
                     LDB is INTEGER
                     The leading dimension of the array B.  LDB >= max(1,N).

           INFO      (output)
                     INFO is INTEGER
                     = 0:  successful exit
                     < 0:  if INFO = -i, the i-th argument had an illegal value



LAPACK routine                  31 October 2017                      DSYTRS(3)