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Author Hansen, Wilfred J.
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Language English
Subject Keyword Deadlock ♦ Acyclic digraph ♦ Database integrity ♦ List processing ♦ Network ♦ Data structures ♦ Topological sort
Abstract A progressive acyclic diagraph (PAD) algorithm accepts are requests and maintains a graph in an acyclic state. When a request creates a cycle, nodes are “detached” until the new arc can be entered acyclically. This process is important in certain areas of database implementation in which there are constraints on the permissible sequences of actions.Two PAD algorithms are presented; one uses a simple path matrix representation and the other uses a list with an “artificial gradient.” Experiments suggest that for large N the second is considerably faster, though both are asymptotically O(NR), where N is the number of nodes and R is the expected number of nodes reachable along paths from any given node.
Description Affiliation: Univ. of Illinois at Urbana-Champaign (Hansen, Wilfred J.)
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2005-08-01
Publisher Place New York
Journal Communications of the ACM (CACM)
Volume Number 22
Issue Number 9
Page Count 6
Starting Page 513
Ending Page 518

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Source: ACM Digital Library