zptt01.f3
Usage
Functions/Subroutines
subroutine zptt01 (n, d, e, df, ef, work, resid)
ZPTT01
Function/Subroutine Documentation
subroutine zptt01 (integer n, double precision, dimension( * ) d, complex*16, dimension( * ) e, double precision, dimension( * ) df, complex*16, dimension( * ) ef, complex*16, dimension( * ) work, double precision resid)
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.