Supporting Irregular Distributions Using S DatacParallel Languages
نویسندگان
چکیده
12 0 n distributed-memory machines, large data arrays need to be partitioned between local processor memories. These partitioned data arrays are called distributed arrays. Many applications can be efficiently implemented by using simple schemes for mapping distributed arrays. One such scheme is BLOCK distribution, which divides an array into contiguous, equal-sized subarrays and assigns each subarray to a different processor. Another is CYCLIC distribution, which assigns consecutively indexed array elements to processors in round-robin fashion. However, more complex distributions are required to efficiently execute in-egularpl-oblem such as computational fluid dynamics codes, molecular dynamics codes, diagonal or polynomial preconditioned iterative linear solvers, and time-dependent flame-modeling codes. Researchers have developed a variety of methods to obtain data mappings that optimize the communication requirements of irregular problems. 1-3 These methods produce irregular distributions. The Fortran D,“ Fortran 90D, and Vienna Fortranj data-parallel languages support irregular data distributions. Fortran D and Fortran 90D let a programmer explicitly specify an irregular distribution using an array, to specify a mapping of array elements to processors. (Fortran D is Fortran 77 with data distribution; Fortran 90D is Fortran 90 with data distribution.) Vienna Fortran lets developers define functions to describe irregular distributions. However, the current version of High Performance Fortran does not directly support irregular distributions6 Also, in irregular problems, data-access patterns and workload are usu-
منابع مشابه
A Novel Compilation Framework for Supporting Semi-Regular Distributions in Hybrid Applications
This paper explains how efficient support for semiregular distributions can be incorporated in a uniform compilation framework for hybrid applications. The key focus of this work is in showing how, unlike other existing schemes, our scheme is able to minimize preprocessing overheads and maintain sophisticated communication optimizations (such as reduction of inter-processor communication during...
متن کاملIrregular Data-parallel Objects in C++ 1 Irregularity and Data-parallelism
Most data-parallel languages use arrays to support paral-lelism. This regular data structure allows a natural development of regular parallel algorithms. The implementation of irregular algorithms requires a programming eeort to project the irregular data structures onto regular structures. We rst propose in this paper a classiication of existing data-parallel languages. We brieey describe thei...
متن کاملSupporting Irregular and Dynamic Computations in Data Parallel Languages
Data-parallel languages support a single instruction ow; the parallelism is expressed at the instruction level. Actually, data-parallel languages have chosen arrays to support the parallelism. This regular data structure allows a natural development of regular parallel algorithms. The implementation of irregular algorithms necessitates a programming eeort to project the irregular data structure...
متن کاملVertex Degree Distribution for the Graph of Word Co-Occurrences in Russian
Degree distributions for word forms cooccurrences for large Russian text collections are obtained. Two power laws fit the distributions pretty good, thus supporting Dorogovtsev-Mendes model for Russian. Few different Russian text collections were studied, and statistical errors are shown to be negligible. The model exponents for Russian are found to differ from those for English, the difference...
متن کامل