dgttrs.f(3)

NAME
dgttrs.f -

SYNOPSIS

  Functions/Subroutines
subroutine dgttrs (TRANS, N, NRHS, DL, D, DU, DU2, IPIV, B, LDB, INFO)
DGTTRS

Function/Subroutine Documentation

  subroutine dgttrs (characterTRANS, integerN, integerNRHS, double precision, dimension( * )DL, double precision, dimension( * )D, double precision, dimension( * )DU, double precision, dimension( * )DU2, integer, dimension( * )IPIV, double precision, dimension( ldb, * )B, integerLDB, integerINFO)

DGTTRS

Purpose:

     DGTTRS 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:
    TRANS

              TRANS is CHARACTER*1
              Specifies the form of the system of equations.
              = 'N':  A * X = B  (No transpose)
              = 'T':  A**T* X = B  (Transpose)
              = 'C':  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).

    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.

Date:
    September 2012

Definition at line 138 of file dgttrs.f.

Author

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