TESTING/LIN/sgtt01.f(3)

NAME
TESTING/LIN/sgtt01.f

SYNOPSIS

  Functions/Subroutines
subroutine sgtt01 (n, dl, d, du, dlf, df, duf, du2, ipiv, work, ldwork, rwork, resid)
SGTT01

Function/Subroutine Documentation

  subroutine sgtt01 (integer n, real, dimension( * ) dl, real, dimension( * ) d, real, dimension( * ) du, real, dimension( * ) dlf, real, dimension( * ) df, real, dimension( * ) duf, real, dimension( * ) du2, integer, dimension( * ) ipiv, real, dimension( ldwork, * ) work, integer ldwork, real, dimension( * ) rwork, real resid)

SGTT01

Purpose:

     SGTT01 reconstructs a tridiagonal matrix A from its LU factorization
     and computes the residual
        norm(L*U - A) / ( norm(A) * EPS ),
     where EPS is the machine epsilon.

Parameters
    N

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

    DL

              DL is REAL array, dimension (N-1)
              The (n-1) sub-diagonal elements of A.

    D

              D is REAL array, dimension (N)
              The diagonal elements of A.

    DU

              DU is REAL array, dimension (N-1)
              The (n-1) super-diagonal elements of A.

    DLF

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

    DF

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

    DUF

              DUF is REAL array, dimension (N-1)
              The (n-1) elements of the first super-diagonal of U.

    DU2

              DU2 is REAL 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.

    WORK

              WORK is REAL array, dimension (LDWORK,N)

    LDWORK

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

    RWORK

              RWORK is REAL array, dimension (N)

    RESID

              RESID is REAL
              The scaled residual:  norm(L*U - A) / (norm(A) * EPS)

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 132 of file sgtt01.f.

Author

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