TESTING/LIN/zptt01.f(3) Library Functions Manual TESTING/LIN/zptt01.f(3)

TESTING/LIN/zptt01.f


subroutine zptt01 (n, d, e, df, ef, work, resid)
ZPTT01

ZPTT01

Purpose:

!>
!> ZPTT01 reconstructs a tridiagonal matrix A from its L*D*L'
!> factorization and computes the residual
!>    norm(L*D*L' - A) / ( n * norm(A) * EPS ),
!> where EPS is the machine epsilon.
!> 

Parameters

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

D

!>          D is DOUBLE PRECISION array, dimension (N)
!>          The n diagonal elements of the tridiagonal matrix A.
!> 

E

!>          E is COMPLEX*16 array, dimension (N-1)
!>          The (n-1) subdiagonal elements of the tridiagonal matrix A.
!> 

DF

!>          DF is DOUBLE PRECISION array, dimension (N)
!>          The n diagonal elements of the factor L from the L*D*L'
!>          factorization of A.
!> 

EF

!>          EF is COMPLEX*16 array, dimension (N-1)
!>          The (n-1) subdiagonal elements of the factor L from the
!>          L*D*L' factorization of A.
!> 

WORK

!>          WORK is COMPLEX*16 array, dimension (2*N)
!> 

RESID

!>          RESID is DOUBLE PRECISION
!>          norm(L*D*L' - A) / (n * norm(A) * EPS)
!> 

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 91 of file zptt01.f.

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