ZGTT01 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*16 array, dimension (N-1)


          The (n-1) sub-diagonal elements of A.

D

          D is COMPLEX*16 array, dimension (N)


          The diagonal elements of A.

DU

          DU is COMPLEX*16 array, dimension (N-1)


          The (n-1) super-diagonal elements of A.

DLF

          DLF is COMPLEX*16 array, dimension (N-1)


          The (n-1) multipliers that define the matrix L from the


          LU factorization of A.

DF

          DF is COMPLEX*16 array, dimension (N)


          The n diagonal elements of the upper triangular matrix U from


          the LU factorization of A.

DUF

          DUF is COMPLEX*16 array, dimension (N-1)


          The (n-1) elements of the first super-diagonal of U.

DU2

          DU2 is COMPLEX*16 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*16 array, dimension (LDWORK,N)

LDWORK

          LDWORK is INTEGER


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

RWORK

          RWORK is DOUBLE PRECISION array, dimension (N)

RESID

          RESID is DOUBLE PRECISION


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

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