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Physical Sciences and Mathematics Commons

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Computer Sciences

Algorithms

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Northeast Parallel Architecture Center

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Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Random Number Generators For Parallel Computers, Paul D. Coddington Jan 1997

Random Number Generators For Parallel Computers, Paul D. Coddington

Northeast Parallel Architecture Center

Random number generators are used in many applications, from slot machines to simulations of nuclear reactors. For many computational science applications, such as Monte Carlo simulation, it is crucial that the generators have good randomness properties. This is particularly true for large-scale simulations done on high-performance parallel computers. Good random number generators are hard to find, and many widely-used techniques have been shown to be inadequate. Finding high-quality, efficient algorithms for random number generation on parallel computers is even more difficult. Here we present a review of the most commonly-used random number generators for parallel computers, and evaluate each generator …


Runtime Array Redistribution In Hpf Programs, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox Jan 1994

Runtime Array Redistribution In Hpf Programs, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox

Northeast Parallel Architecture Center

This paper describes efficient algorithms for runtime array redistribution in HPF programs. We consider block(m) to cyclic, cyclic to block(m) and the general cyclic(x) to cyclic(y) type redistributions. We initially describe algorithms for one-dimensional arrays and then extend the methodology to multidimensional arrays. The algorithms are practical enough to be easily implemented in the runtime library of an HPF compiler and can also be directly used in application programs requiring redistribution. Performance results on the Intel Paragon are discussed.


Scheduling Regular And Irregular Communication Patterns On The Cm-5, Ravi Ponnusamy, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox Jan 1992

Scheduling Regular And Irregular Communication Patterns On The Cm-5, Ravi Ponnusamy, Rajeev Thakur, Alok Choudhary, Geoffrey C. Fox

Northeast Parallel Architecture Center

In this paper, we study the communication characteristics of the CM-5 and the performance effects of scheduling regular and irregular communication patterns on the CM-5. We consider the scheduling of regular communication patterns such as complete exchange and broadcast. We have implemented four algorithms for complete exchange and studied their performances on a 2D FFT algorithm. We have also implemented four algorithms for scheduling irregular communication patterns and studied their performance on the communication patterns of several synthetic as well as real problems such as the conjugate gradient solver and the Euler solver.