GUIDELINES AND COMPUTATIONAL RESULTS FOR VECTOR PROCESSING OF NETWORK ASSIGNMENT CODES ON SUPERCOMPUTERS
Supercomputers derive their computational performance form faster processors as well as innovations in their architecture. To take advantage of the vector processing capabilities of supercomputers, such as the CRAY X-MP series, it is necessary to modify the code to enhance its vector processing performance. These modifications can range from simple localized recoding of existing mainframe codes to devising new algorithms with the hardware's architecture in mind. In this paper, codes for the solution of two network equilibrium assignment problem formulations (Frank-Wolfe algorithm for the single-class user equilibrium problem and the diagonalization algorithm for multiple user classes with asymmetric interactions) are vectorized and tested on a CRAY X-MP/24 supercomputer. Only local vectorization by limited recoding of existing programs is performed. Guidelines are given for this purpose, and their application to the assignment codes is illustrated. The computational tests performed indicate an improvement in execution time of about 70 to 80% of the modified code relative to its unvectorized performance on the CRAY supercomputer. Execution of the vectorized code on the CRAY is about 22 times faster than the execution of the unmodified code on a mainframe computer. The significance of the results for research and practice is also discussed.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/0309050022
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Supplemental Notes:
- This paper appears in Transportation Research Record No. 1251, Transport Supply Analysis. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
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Authors:
- Mahmassani, H S
- Mahmassani, Hani S
- Publication Date: 1989
Media Info
- Features: Figures; References; Tables;
- Pagination: p. 10-16
- Monograph Title: Transport supply analysis
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Serial:
- Transportation Research Record
- Issue Number: 1251
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Calculation; Equilibrium (Systems); Guidelines; Networks; Supercomputers; Traffic assignment; Traffic equilibrium; Vector analysis
- Uncontrolled Terms: Computation
- Old TRIS Terms: Vectors
- Subject Areas: Highways; Planning and Forecasting; I72: Traffic and Transport Planning;
Filing Info
- Accession Number: 00495527
- Record Type: Publication
- ISBN: 0309050022
- Files: TRIS, TRB
- Created Date: Jul 31 1990 12:00AM