cppt01.f3
Usage
Functions/Subroutines
subroutine cppt01 (uplo, n, a, afac, rwork, resid)
CPPT01
Function/Subroutine Documentation
subroutine cppt01 (character uplo, integer n, complex, dimension( * ) a, complex, dimension( * ) afac, real, dimension( * ) rwork, real resid)
CPPT01
Purpose:
!> !> CPPT01 reconstructs a Hermitian positive definite packed matrix A !> from its L*L' or U'*U factorization and computes the residual !> norm( L*L' - A ) / ( N * norm(A) * EPS ) or !> norm( U'*U - A ) / ( N * norm(A) * EPS ), !> where EPS is the machine epsilon, L' is the conjugate transpose of !> L, and U' is the conjugate transpose of U. !>
Parameters
UPLO
!> UPLO is CHARACTER*1 !> Specifies whether the upper or lower triangular part of the !> Hermitian matrix A is stored: !> = 'U': Upper triangular !> = 'L': Lower triangular !>
N
!> N is INTEGER !> The number of rows and columns of the matrix A. N >= 0. !>
A
!> A is COMPLEX array, dimension (N*(N+1)/2) !> The original Hermitian matrix A, stored as a packed !> triangular matrix. !>
AFAC
!> AFAC is COMPLEX array, dimension (N*(N+1)/2) !> On entry, the factor L or U from the L*L' or U'*U !> factorization of A, stored as a packed triangular matrix. !> Overwritten with the reconstructed matrix, and then with the !> difference L*L' - A (or U'*U - A). !>
RWORK
!> RWORK is REAL array, dimension (N) !>
RESID
!> RESID is REAL !> If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS ) !> If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS ) !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 94 of file cppt01.f.