![]() |
LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
|
subroutine zppt01 | ( | character | UPLO, |
integer | N, | ||
complex*16, dimension( * ) | A, | ||
complex*16, dimension( * ) | AFAC, | ||
double precision, dimension( * ) | RWORK, | ||
double precision | RESID | ||
) |
ZPPT01
ZPPT01 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.
[in] | 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 |
[in] | N | N is INTEGER The number of rows and columns of the matrix A. N >= 0. |
[in] | A | A is COMPLEX*16 array, dimension (N*(N+1)/2) The original Hermitian matrix A, stored as a packed triangular matrix. |
[in,out] | AFAC | AFAC is COMPLEX*16 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). |
[out] | RWORK | RWORK is DOUBLE PRECISION array, dimension (N) |
[out] | 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 ) |
Definition at line 97 of file zppt01.f.