We numerically analyze the possibility of turning off post-smoothing (relaxation) in geometric multigrid used as a preconditioner in conjugate gradient linear and eigenvalue solvers for the 3D Laplacian. The geometric Semicoarsening Multigrid (SMG) method is provided by the hypre parallel software package. We solve linear systems using two variants (standard and flexible) of the preconditioned ...

When a symmetric, positive, isomorphism between a reeexive Banach space (that is densely and compactly embedded in a Hilbert space) and its dual varies smoothly over a Banach space, its eigenvalues vary in a Lipschitz manner. We calculate the generalized gradient of the extreme eigenvalues at an arbitrary crossing. We apply this to the generalized gradient, with respect to a coeecient in an ell...

This note gives converses to the well-known result: for any vector e u such that sin (u; e u) = O( ), we have e u Ae u e u e u = + O( ) where is an eigenvalue and u is the corresponding eigenvector of a Hermitian matrix A, and \ " denotes complex conjugate transpose. It shows that if e u Ae u=e u e u is close to A's largest eigenvalue, then e u is close to the corresponding eigenvector with an ...

The polynomial preserving recovery (PPR) is used to enhance the finite element eigenvalue approximation. Remarkable fourth order convergence is observed for linear elements under structured meshes as well as unstructured initial meshes (produced by the Delaunay triangulation) with the conventional bisection refinement.

A novel orthogonalization-free method together with two specific algorithms is proposed to address extreme eigenvalue problems. On top of gradient-based algorithms, the modify multicolumn gradient such that earlier columns are decoupled from later ones. Locally, both converge linearly convergence rates depending on eigengaps. Momentum acceleration, exact linesearch, and column locking incorpora...

Since introduction [A. Knyazev, Toward the optimal preconditioned eigensolver: Locally optimal block preconditioned conjugate gradient method, SISC (2001) doi:10.1137/S1064827500366124] and efficient parallel implementation [A. Knyazev et al., Block locally optimal preconditioned eigenvalue xolvers (BLOPEX) in HYPRE and PETSc, SISC (2007) doi:10.1137/060661624], LOBPCG has been used is a wide r...

An algorithm for recursive Frisch scheme system identification of linear single-input single-output errors-in-variables systems is developed. For the update of the estimated model parameters, a recursive bias-compensating least squares algorithm, which is based on the wellknown recursive least squares technique, is considered. The estimate of the output measurement noise variance is determined ...

A recently proposed linear-scaling scheme for density-functional pseudopotential calculations is described in detail. The method is based on a formulation of density functional theory in which the ground state energy is determined by minimization with respect to the density matrix, subject to the condition that the eigenvalues of the latter lie in the range [0,1]. Linear-scaling behavior is ach...

The Chebyshev tau method is examined in detail for a variety of eigenvalue problems arising in hydrodynamic stability studies, particularly those of Orr-Sommerfeld type. We concentrate on determining the whole of the top end of the spectrum in parameter ranges beyond those often explored. The method employing a Chebyshev representation of the fourth derivative operator, D 4, is compared with th...