Tim Stitt, Ph.D. is a HPC Support Scientist with the Swiss National Supercomputing Centre (CSCS). He wrote an article (or module) on CNX Connections web site introducing PGAS programming model.

Summary:
This module introduces the Partitioned Global Address Space (PGAS) programming paradigm. This paradigm provides both a data and execution model that has the potential to dramatically improve runtime performance and programmer productivity on increasingly ubiquitous multi-core architectures. The fundamental principles of the PGAS paradigm are presented in comparison with traditional parallel programming models. Furthermore, the richer ‘Asynchronous PGAS’ programming model is also introduced in association with the next-generation parallel programming languages Chapel and X10.

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Ideally a successful parallel programming model should hope to marry the performance and data locality (partitioning) features of MPI with the programmability and data referencing simplicity of a shared-memory (global address space) model.

The PGAS programming model aims to achieve these characteristics by providing:

1. a local-view programming style (which differentiates between local and remote data partitions)
2. a global address space (which is directly accessible by any process)
3. compiler-introduced communication to resolve remote references
4. one-sided communication for improved inter-process performance
5. support for distributed data structures

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