In this paper, a recently introduced block circulant preconditioner for the linear systems of the codes for ordinary differential equations (ODEs) is investigated. Most ODE codes based on implicit formulas, at each integration step, need the solution of one or more unsymmetric linear systems that are often large and sparse. Here, the boundary value methods, a class of implicit methods for the n...

We consider the LU factorization of unsymmetric sparse matrices using a threephase approach (analysis, factorization and triangular solution). Usually the analysis phase first determines a set of potentially good pivot and then orders this set of pivots to decrease the fill-in in the factors. In this paper, we present a preprocessing algorithm that simultaneously achieves the objectives of sele...

New synthetic routes to symmetric and unsymmetric dppm-type chelate linkers containing the ethoxysilane group are described and the compounds were characterized also by solid-state NMR spectroscopy and X-ray structures.

Voluminous amides were coupled with deactivated, sterically hindered aryl chlorides in excellent yields providing products, which have not been efficiently accessible by transition metal catalysis so far. Application of an unsymmetric bisphosphine ligand was critical for the high catalytic activity.

In the present paper we study the ideal of all subsets of 3?°> for which the second player has a winning strategy in the unsymmetric game. We describe its cardinal coefficients and the notions of forcing determined by it.

A novel unsymmetric square matrix, WPU , is proposed for calculating both Wiener, W , and hyper-Wiener, WW, numbers. This matrix is constructed by using single endpoint characterization of paths. Its relations with Wiener-type numbers are discussed.

For most unsymmetric matrices it is difficult to compute many accurate eigenvalues using the primitive form of the unsymmetric Lanczos algorithm (ULA). In this paper we propose a modification of the ULA. It is related to ideas used in [J. Chem. Phys. 122 (2005), 244107 (11 pages)] to compute resonance lifetimes. Using the refined ULA we suggest, the calculation of accurate extremal and interior...