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Retrieval of scattered information by EREW, CREW and CRCW PRAMs

  • Faith Fich
  • Miroslaw Kowaluk
  • Krzysztof Loryś
  • Miroslaw Kutylowski
  • Prabhakar Ragde
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 621)

Abstract

The k-compaction problem arises when k out of n cells in an array are non-empty and the contents of these cells must be moved to the first k locations in the array. Parallel algorithms for k-compaction have obvious applications in processor allocation and load balancing; k-compaction is also an important subroutine in many recently developed parallel algorithms. We show that any EREW PRAM that solves the k-compaction problem requires Ω(√log n) time, even if the number of processors is arbitrarily large and k=2. On the CREW PRAM, we show that every n-processor algorithm for k-compaction problem requires Ω(loglog n) time, even if k=2. Finally, we show that O(log k) time can be achieved on the ROBUST PRAM, a very weak CRCW PRAM model.

Keywords

Memory Cell Parallel Algorithm Output Cell Boolean Variable Answer Cell 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • Faith Fich
    • 1
    • 2
  • Miroslaw Kowaluk
    • 3
  • Krzysztof Loryś
    • 3
  • Miroslaw Kutylowski
    • 4
  • Prabhakar Ragde
    • 5
  1. 1.University of TorontoTorontoCanada
  2. 2.MITCambridgeUSA
  3. 3.Universität WürzburgWürzburgGermany
  4. 4.FB Informatik and Heinz-Nixdorf-InstitutUniversität-GH PaderbornPaderbornGermany
  5. 5.University of WaterlooWaterlooCanada

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