SRC/dgtts2.f(3)

NAME
SRC/dgtts2.f

SYNOPSIS

  Functions/Subroutines
subroutine dgtts2 (itrans, n, nrhs, dl, d, du, du2, ipiv, b, ldb)
DGTTS2 solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by sgttrf.

Function/Subroutine Documentation

  subroutine dgtts2 (integer itrans, integer n, integer nrhs, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( * ) du2, integer, dimension( * ) ipiv, double precision, dimension( ldb, * ) b, integer ldb)

DGTTS2 solves a system of linear equations with a tridiagonal matrix using the LU factorization computed by sgttrf.

Purpose:

     DGTTS2 solves one of the systems of equations
        A*X = B  or  A**T*X = B,
     with a tridiagonal matrix A using the LU factorization computed
     by DGTTRF.

Parameters
    ITRANS

              ITRANS is INTEGER
              Specifies the form of the system of equations.
              = 0:  A * X = B  (No transpose)
              = 1:  A**T* X = B  (Transpose)
              = 2:  A**T* X = B  (Conjugate transpose = Transpose)

    N

              N is INTEGER
              The order of the matrix A.

    NRHS

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

    DL

              DL is DOUBLE PRECISION array, dimension (N-1)
              The (n-1) multipliers that define the matrix L from the
              LU factorization of A.

    D

              D is DOUBLE PRECISION array, dimension (N)
              The n diagonal elements of the upper triangular matrix U from
              the LU factorization of A.

    DU

              DU is DOUBLE PRECISION array, dimension (N-1)
              The (n-1) elements of the first super-diagonal of U.

    DU2

              DU2 is DOUBLE PRECISION array, dimension (N-2)
              The (n-2) elements of the second super-diagonal of U.

    IPIV

              IPIV is INTEGER array, dimension (N)
              The pivot indices; for 1 <= i <= n, row i of the matrix was
              interchanged with row IPIV(i).  IPIV(i) will always be either
              i or i+1; IPIV(i) = i indicates a row interchange was not
              required.

    B

              B is DOUBLE PRECISION array, dimension (LDB,NRHS)
              On entry, the matrix of right hand side vectors B.
              On exit, B is overwritten by the solution vectors X.

    LDB

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

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 127 of file dgtts2.f.

Author

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