SRC/dgtsv.f(3)

NAME
SRC/dgtsv.f

SYNOPSIS

  Functions/Subroutines
subroutine dgtsv (n, nrhs, dl, d, du, b, ldb, info)
DGTSV computes the solution to system of linear equations A * X = B for GT matrices

Function/Subroutine Documentation

  subroutine dgtsv (integer n, integer nrhs, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( ldb, * ) b, integer ldb, integer info)

DGTSV computes the solution to system of linear equations A * X = B for GT matrices

Purpose:

    !>
    !> DGTSV  solves the equation
    !>
    !>    A*X = B,
    !>
    !> where A is an n by n tridiagonal matrix, by Gaussian elimination with
    !> partial pivoting.
    !>
    !> Note that the equation  A**T*X = B  may be solved by interchanging the
    !> order of the arguments DU and DL.
    !>

Parameters
    N

    !>          N is INTEGER
    !>          The order of the matrix A.  N >= 0.
    !>

    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)
    !>          On entry, DL must contain the (n-1) sub-diagonal elements of
    !>          A.
    !>
    !>          On exit, DL is overwritten by the (n-2) elements of the
    !>          second super-diagonal of the upper triangular matrix U from
    !>          the LU factorization of A, in DL(1), ..., DL(n-2).
    !>

    D

    !>          D is DOUBLE PRECISION array, dimension (N)
    !>          On entry, D must contain the diagonal elements of A.
    !>
    !>          On exit, D is overwritten by the n diagonal elements of U.
    !>

    DU

    !>          DU is DOUBLE PRECISION array, dimension (N-1)
    !>          On entry, DU must contain the (n-1) super-diagonal elements
    !>          of A.
    !>
    !>          On exit, DU is overwritten by the (n-1) elements of the first
    !>          super-diagonal of U.
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
    !>          On entry, the N by NRHS matrix of right hand side matrix B.
    !>          On exit, if INFO = 0, the N by NRHS solution matrix 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
    !>          > 0: if INFO = i, U(i,i) is exactly zero, and the solution
    !>               has not been computed.  The factorization has not been
    !>               completed unless i = N.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 126 of file dgtsv.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.