TESTING/LIN/sppt01.f(3) | Library Functions Manual | TESTING/LIN/sppt01.f(3) |
NAME
TESTING/LIN/sppt01.f
SYNOPSIS
Functions/Subroutines
subroutine sppt01 (uplo, n, a, afac, rwork, resid)
SPPT01
Function/Subroutine Documentation
subroutine sppt01 (character uplo, integer n, real, dimension( * ) a, real, dimension( * ) afac, real, dimension( * ) rwork, real resid)
SPPT01
Purpose:
SPPT01 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 REAL array, dimension (N*(N+1)/2) The original symmetric matrix A, stored as a packed triangular matrix.
AFAC
AFAC is REAL 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 92 of file sppt01.f.
Author
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