Retrieval of scattered information by EREW, CREW and CRCW PRAMs

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 ( 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 (log log 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. supported by NSERC and the Information Technology Research Centre of Ontario supported by Deutsche Forschungsgemeinschaft under grant Wa 549/1; present address: Uniwersytet Warszawski, ul. Banacha 2, PL-02-097 Warszawa, Poland supported by the Alexander ...

• Type: Conference
• Year: 1992
• Where: SWAT
• Authors: Faith E. Fich, Miroslaw Kowaluk, Krzysztof Lorys, Miroslaw Kutylowski, Prabhakar Ragde
• Keywords: Algorithms, K-compaction Problem, Present Address, SWAT 1992, Technology Research Centre