Volume 19, 2000, No. 4


SOME PITFALLS OF PARALLEL LOGIC PROGRAMMING

Steven Prestwich

Abstract. Logic programs are highly amenable to parallelization, and their  level of abstraction relieves the programmer of many of the most difficult and error-prone details of parallel programming.  However, tuning the performance of a parallel logic program is nontrivial.  While working with programmers we noticed that they evolved strategies based on observed parallel performance. This paper illustrates some pitfalls inherent in this approach, using simple examples whose behaviour  does not depend upon a particular task scheduling algorithm, and which are mostly non-speculative and therefore of general interest. It has two aims: to make parallel logic programmers more aware of such  pitfalls, and to pose a challenge to future runtime analysis tools.

GENERALIZED ROYAL ROAD FUNCTIONS AND THEIR EPISTASIS

Bart Naudts, Dominique Suys, Alain Verschoren

Keywords: Royal road function, complexity, epistasis, genetic algorithm

ON DERIVATIVES ESTIMATION OF SMOOTHED  DIGITAL CURVES

Ján Glasa

Abstract. In this paper new linear operators for the first derivatives estimation of smoothed digital curves are presented. They correspond to digital curves smoothing by various non-negative kernels.

LOAD BALANCING ISSUES IN THE PREPARTITIONING  METHOD

Jerôme Galtier

Abstract. An original approach to the partitioning of 3D meshes (typically for the finite element method) is presented. Our technique applies on sub-domains defined by their polyhedrical boundary. It relies on the meshing of interfaces between sub-domains before meshing the domain itself. Since this idea basically trades smoothness, small-size, and regularity of the interfaces for unbalance, we describe a fast, efficient, linear-time evaluation algorithm that corrects this default. Its use is experienced with industrial benchmarks, and compared with other heuristic schemes.

 

COMPREHENDING LOOPS IN A PROCESS FUNCTIONAL PROGRAMMING LANGUAGE

Ján Kollár

Abstract. In this paper the implementation of loops in PFL - a process functional programming language is presented. The uniform conception of functions and processes in PFL makes possible to implement loops in a way similar to list comprehensions. Using process functional paradigm we will show, how the imperative loops are expressed more concisely in a purely functional manner preserving the run-time efficiency.


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