SRC/zgttrf.f(3)

NAME
SRC/zgttrf.f

SYNOPSIS

  Functions/Subroutines
subroutine zgttrf (n, dl, d, du, du2, ipiv, info)
ZGTTRF

Function/Subroutine Documentation

  subroutine zgttrf (integer n, complex*16, dimension( * ) dl, complex*16, dimension( * ) d, complex*16, dimension( * ) du, complex*16, dimension( * ) du2, integer, dimension( * ) ipiv, integer info)

ZGTTRF

Purpose:

     ZGTTRF computes an LU factorization of a complex tridiagonal matrix A
     using elimination with partial pivoting and row interchanges.
     The factorization has the form
        A = L * U
     where L is a product of permutation and unit lower bidiagonal
     matrices and U is upper triangular with nonzeros in only the main
     diagonal and first two superdiagonals.

Parameters
    N

              N is INTEGER
              The order of the matrix A.

    DL

              DL is COMPLEX*16 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-1) multipliers that
              define the matrix L from the LU factorization of A.

    D

              D is COMPLEX*16 array, dimension (N)
              On entry, D must contain the diagonal elements of A.
              On exit, D is overwritten by the n diagonal elements of the
              upper triangular matrix U from the LU factorization of A.

    DU

              DU is COMPLEX*16 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.

    DU2

              DU2 is COMPLEX*16 array, dimension (N-2)
              On exit, DU2 is overwritten by 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.

    INFO

              INFO is INTEGER
              = 0:  successful exit
              < 0:  if INFO = -k, the k-th argument had an illegal value
              > 0:  if INFO = k, U(k,k) is exactly zero. The factorization
                    has been completed, but the factor U is exactly
                    singular, and division by zero will occur if it is used
                    to solve a system of equations.

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 123 of file zgttrf.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.