Concurrency and Computation: Practice & Experience

doi: 10.1002/cpe.4330050501pmid: N/A

Teng, Y. Ansel; Dementhon, Daniel; Davis, Larry S.

doi: 10.1002/cpe.4330050502pmid: N/A

We propose an algorithm for solving region‐to‐region visibility problems on digital terrain models using data parallel machines. Since global communication is the bottleneck in this kind of algorithm, the algorithm we propose focuses on the reduction of global communication. The algorithm analyses a strip of the source region at a time and sweeps through the source strip by strip. At most four sweeps are needed for the analysis. By exploring the coherence properties in the processor structure, global communication is minimized and complexity is substantially improved. Furthermore, all global write operations are exclusive and concurrency in global read operations is minimized. Since the problem size is usually large, we also designed rules of decomposition to efficiently handle the cases where the required number of processors is greater than available. The algorithm has been implemented on a Connection Machine CM‐2, and results of computational experiments are presented.

Hansen, Per Brinch

doi: 10.1002/cpe.4330050503pmid: N/A

We describe a programming methodology for computational science based on programming paradigms for multicomputers. Each paradigm is a class of algorithms that have the same control structure. For every paradigm, a general parallel program is developed. The general program is then used to derive two or more model programs, which solve specific problems in science and engineering. These programs have been tested on a Computing Surface and published with every detail open to scrutiny. We explain the steps involved in developing model programs and conclude that the study of programming paradigms provides an architectural vision of parallel scientific computing.

Hansen, Per Brinch

doi: 10.1002/cpe.4330050504pmid: N/A

We develop a model program for parallel execution of cellular automata on a multicomputer. The model program is then adapted for simulation of forest fires and numerical solution of Laplace's equation for stationary heat flow. The performance of the parallel program is analyzed and measured on a Computing Surface configured as a matrix of transputers with distributed memory.