tailieunhanh - PELLPACK: A Problem Solving Environment for PDE Based Applications on Multicomputer Platforms
Developing countries devote all their available capacities to safeguard their small and poor farmers from being sidelined by things like growing competition through efficient support measures. They use their flexibilities to provide production-linked support to the fullest extent as, on the one hand, such payments are easier to administer and as they help creating basic food security by increasing production of staple crops. Support to rural development in general and to the environment would rank lower. This option could be recommended for developing countries with small financial resources, with large shares in rural low income population, with highly insecure food conditions and only a few environmentally sensitive areas | PELLPACK A Problem Solving Environment for PDE Based Applications on Multicomputer Platforms E. N. Houstis J. R. Rice S. Weerawarana A. C. Catlin P. Papachiou . Wang and M. Gaitatzes Abstract This paper presents the software architecture and implementation of the problem solving environment PSE PELLPACK for modeling physical objects described by partial differential equations PDEs . The scope of this PSE is broad as PELLPACK incorporates many PDE solving systems and some of these in turn include several specific PDE solving methods. Its coverage for 1-D 2-D and 3-D elliptic or parabolic problems is quite broad and it handles some hyperbolic problems. Since a PSE should provide complete support for the problem solving process PELLPACK also contains a large amount of code to support graphical user interfaces analytic tools user help domain or mesh partitioning machine and data selection visualization and various other tasks. Its total size is well over 1 million lines of code. Its open-ended software architecture consists of several software layers. The top layer is an interactive graphical interface for specifying the PDE model and its solution framework. This interface saves the results of the user specification in the form of a very high level PDE language which is an alternative interface to the PELL-PACK system. This language also allows a user to specify the PDE problem and its solution framework textually in a natural form. The PELLPACK language preprocessor generates a Fortran control program with the interfaces calls to specified components and libraries of the PDE solution framework and functions defining the PDE problem. The PELLPACK program execution is supported by a high level tool where the virtual parallel system is defined where the execution mode file system and hardware resources are selected and where the compilation loading and execution are controlled. Finally the PELLPACK PSE integrates several PDE libraries and PDE systems available in the
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