About This Item

Ask the MINDS@UW Librarian

Deja Vu in Fixpoints of Logic Programs

Show full item record

File(s):

Author(s)
Maher, Michael J; Ramakrishnan, Raghu
Publisher
University of Wisconsin-Madison Department of Computer Sciences
Date
Mar 15, 2012
Abstract
We investigate properties of logic programs that permit refinements in their fixpoint evaluation and shed light on the choice of control strategy. A fundamental aspect of a bottom-up computation is that we must constantly check to see if the fixpoint has been reached. If the computation iteratively applies all rules, bottom-up, until the fixpoint is reached, this amounts to checking if any new facts were produced after each iteration. Such a check also enhances efficiency in that duplicate facts needs not be re-used in subsequent interations, if we use the Seminaive fixpoint evaluation strategy. However, the cost of this check is a significant component of the cost of bottom-up fixpoint evaluation, and for many programs the full check is unnecessary. We identify properties of programs that enable us to infer that a much simpler check (namely, whether any fact was produced in the previous iteration) suffices. While it is in general undecidable whether a given program has these properties, we develop techniques to test sufficient conditions, and we illustrate these techniques on some simple programs that have these properties.
Permanent link
http://digital.library.wisc.edu/1793/59216 
Export
Export to RefWorks 
‚Äč

Part of

Show full item record

Search and browse




About MINDS@UW

Deposit materials

  1. Register to deposit in MINDS@UW
  2. Need deposit privileges? Contact us.
  3. Already registered? Have deposit privileges? Deposit materials.