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In this paper, we present and analyse some local and parallel covolume algorithms for second-order elliptic problems. We first prove some local a priori error estimates for covolume method. With these results, we shall apply the two-grid strategy to covolume approximation to give two novel covolume algorithms, and show that the convergence rates of these algorithms are optimal in piecewise H1-norm. Numerical results confirming the theory are also provided. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The redistribution and embedding are two main adaptive-grid methods. With use of initial structured grid, it is possible to combine these adaptive-grid techniques. It means that before the grid becomes unstructured, we employ redistribution technique and then use embedding method. It is used to solve three model problems, transonic and supersonic inviscid flows in channels with circular arc bump and with convergent part. The Euler equations are integrated to steady state by an explicit, finite volume, Ni's Lax–Wendroff type. The combination of adaptive-grid redistribution and embedding is complex, but it is shown in this paper that it is very efficient and worth to use it in large CPU time consuming problems. The results also show that the combination requires less grid points and therefore less memory space for prescribed accuracy. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper numerical methods for solving first-order hyperbolic partial differential equations are developed. These methods are developed by approximating the first-order spatial derivative by third-order finite-difference approximations and a matrix exponential function by a third-order rational approximation having distinct real poles. Then parallel algorithms are developed and tested on a sequential computer for an advection equation with constant coefficient and a non-linear problem. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper describes an analytical model for a beam system, based on a modified Timoshenko theory, where the beam is pinned to a hub driven by an actuator at one end and is subject to a heavy load at the other end. A new efficient computational algorithm is then proposed for solving the higher-order non-canonical partial differential equation model, which is developed based on the generalized difference method. This allows a suitable selection of different trial and test spaces, so as to improve the computational efficiency while preserving the high convergence rate of the standard finite element method. With the trial space of cubic Hermite finite elements and the test space of piecewise linear functions, the computational scheme reduces to a semi-discretized or even fully discretized computational algorithm. A numerical simulation result is included to visualize the theoretical modelling and computational results. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Based on the concept of the Laplacian matrix of a graph, this paper presents the SGPD (spectral graph pseudoperipheral and pseudodiameter) algorithm for finding a pseudoperipheral vertex or the end-points of a pseudodiameter in a graph. This algorithm is compared with the ones by Grimes eta!. (1990), George and Liu (1979), and Gibbs et a!. (1976). Numerical results from a collection of benchmark test problems show the effectiveness of the proposed algorithm. Moreover, it is shown that this algorithm can be efficiently used in conjunction with heuristic algorithms for ordering sparse matrix equations. Such heuristic algorithms, of course, must be the ones which use the pseudoperipheral vertex or pseudodiameter concepts [ABSTRACT FROM AUTHOR]