!>
!> CGTT01 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.
!> 

N

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

DL

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

D

!>          D is COMPLEX array, dimension (N)
!>          The diagonal elements of A.
!> 

DU

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

DLF

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

DF

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

DUF

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

DU2

!>          DU2 is COMPLEX 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 COMPLEX 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)
!> 

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