4 research outputs found

    A design methodology for portable software on parallel computers

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    This final report for research that was supported by grant number NAG-1-995 documents our progress in addressing two difficulties in parallel programming. The first difficulty is developing software that will execute quickly on a parallel computer. The second difficulty is transporting software between dissimilar parallel computers. In general, we expect that more hardware-specific information will be included in software designs for parallel computers than in designs for sequential computers. This inclusion is an instance of portability being sacrificed for high performance. New parallel computers are being introduced frequently. Trying to keep one's software on the current high performance hardware, a software developer almost continually faces yet another expensive software transportation. The problem of the proposed research is to create a design methodology that helps designers to more precisely control both portability and hardware-specific programming details. The proposed research emphasizes programming for scientific applications. We completed our study of the parallelizability of a subsystem of the NASA Earth Radiation Budget Experiment (ERBE) data processing system. This work is summarized in section two. A more detailed description is provided in Appendix A ('Programming Practices to Support Eventual Parallelism'). Mr. Chrisman, a graduate student, wrote and successfully defended a Ph.D. dissertation proposal which describes our research associated with the issues of software portability and high performance. The list of research tasks are specified in the proposal. The proposal 'A Design Methodology for Portable Software on Parallel Computers' is summarized in section three and is provided in its entirety in Appendix B. We are currently studying a proposed subsystem of the NASA Clouds and the Earth's Radiant Energy System (CERES) data processing system. This software is the proof-of-concept for the Ph.D. dissertation. We have implemented and measured the performance of a portion of this subsystem on the Intel iPSC/2 parallel computer. These results are provided in section four. Our future work is summarized in section five, our acknowledgements are stated in section six, and references for published papers associated with NAG-1-995 are provided in section seven

    Integrating compile-time and runtime parallelism management through revocable thread serialization

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 125-128).by Gino K. Maa.Ph.D

    Petroleum Reservoir Simulation Using 3-D Finite Element Method With Parallel Implementation.

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    Modeling fluid flow around wellbores with conventional reservoir simulators is inaccurate because radial flow occurs in the vicinity of the wellbore and these simulators use cartesian coordinates. In this research, we present a more accurate wellbore simulation by incorporating the finite element method (FEM) to simulate the radial flow in the vicinity of the wellbore and interfacing this finite element wellbore model with an existing finite difference method (FDM) reservoir simulator. Although this technique was developed for a vertical well, it could also be used to accurately model a horizontal wellbore. This hybrid solution is for three dimensional---triphasic fluid flow and allows a more rigorous treatment of the near-well flow. The reservoir region, where flow geometry is linear, is simulated with the cartesian grid using finite differences. The reservoir simulator used for this research was the US Department of Energy\u27s Black Oil Applied Simulation Tool (BOAST II). Two problems furnished by the Department of Energy were used to test the effectiveness of our solution. The first was a single stratum three phase system. The second was a three strata three phase gas injection problem. Finally, our stand alone model could actually be interfaced with almost any other finite difference fluid flow simulator; whether it is for petroleum reservoirs, underground water, or hazardous waste management

    On effective execution of nonuniform DOACROSS loops

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