This article studies the problem of modifying the action ordering of a plan in order to optimise the plan according to various criteria. One of these criteria is to make a plan less constrained and the other is to minimize its parallel execution time. Three candidate de nitions are proposed for the rst of these criteria, constituting a sequence of increasing optimality guarantees. Two of these ...

The solution of chemical process engineering problems often requires the repeated solution of large sparse linear systems of equations that have a highly asymmetric structure. The frontal method can be very e cient for solving such systems on modern computer architectures because, in the innermost loop of the computation, the method exploits dense linear algebra kernels, which are straightforwa...

The single-row facility layout problem (SRFLP) is an NP-hard combinatorial optimization problem that is concerned with the arrangement of n departments of given lengths on a line so as to minimize the weighted sum of the distances between department pairs. (SRFLP) is the one-dimensional version of the facility layout problem that seeks to arrange rectangular facilities so as to minimize the ove...

In this paper we present HUND, a hypergraph-based unsymmetric nested dissection ordering algorithm for reducing the fill-in incurred during Gaussian elimination. HUND has several important properties. It takes a global perspective of the entire matrix, as opposed to local heuristics. It takes into account the assymetry of the input matrix by using a hypergraph to represent its structure. It is ...

Hierarchically-blocked non-linear storage layouts, such as the Morton ordering, have been proposed as a compromise between row-major and columnmajor for two-dimensional arrays. Morton layout offers some spatial locality whether traversed row-wise or column-wise. The goal of this paper is to make this an attractive compromise, offering close to the performance of row-major traversal of row-major...

A bipartite graph G = (V,W,E) is convex if there exists an ordering of the vertices of W such that, for each v ∈ V , the neighbors of v are consecutive in W . In this work, we address the Hamiltonian Circuit Problem, a wellknown problem in Combinatorial Optimization. We present a novel sequential linear-time algorithm for determining a Hamiltonian circuit in convex bipartite graphs which can be...

A parallel implementation of the numerical simulation of a GaAs MESFET device using the finite difference discretisation scheme and solved by a point iterative method is presented. Parallel techniques targeted at Multiple-Instructions Multiple-Data (MIMD) message-passing distributed memory architectures, in particular, Transputers, are described. Efficient parallelism is achieved by the geometr...

Let A and B be two groups of up to n elements distributed on the rst row of an n n reconng-urable mesh, and CA;B a subset of the cartesian product A B satisfying some unknown condition C. Only one broadcasting step is needed in order to compute CA;B's elements. However, the problem of moving CA;B's elements to the rst row in optimal time (so that they can be further processed) is not trivial. T...