TESTING/LIN/dppt01.f(3) Library Functions Manual TESTING/LIN/dppt01.f(3)

TESTING/LIN/dppt01.f


subroutine dppt01 (uplo, n, a, afac, rwork, resid)
DPPT01

DPPT01

Purpose:

!>
!> DPPT01 reconstructs a symmetric 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.
!> 

Parameters

UPLO
!>          UPLO is CHARACTER*1
!>          Specifies whether the upper or lower triangular part of the
!>          symmetric 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 DOUBLE PRECISION array, dimension (N*(N+1)/2)
!>          The original symmetric matrix A, stored as a packed
!>          triangular matrix.
!> 

AFAC

!>          AFAC is DOUBLE PRECISION 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 DOUBLE PRECISION array, dimension (N)
!> 

RESID

!>          RESID is DOUBLE PRECISION
!>          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 92 of file dppt01.f.

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK