dppt01.f - Man Page
TESTING/LIN/dppt01.f
Synopsis
Functions/Subroutines
subroutine dppt01 (uplo, n, a, afac, rwork, resid)
DPPT01
Function/Subroutine Documentation
subroutine dppt01 (character uplo, integer n, double precision, dimension( * ) a, double precision, dimension( * ) afac, double precision, dimension( * ) rwork, double precision resid)
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.
Author
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Referenced By
The man page dppt01(3) is an alias of dppt01.f(3).
Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK