Partial lazy forward checking

Partial forward checking (PFC) may perform more consistency checks than really needed to detect dead-ends in MAX-CSP. After analyzing PFC, we have identified four causes of redundant check computation: (a) unnecessary lookahead when detecting an empty domain, (b) not always using the better bounds f...

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Detalles Bibliográficos
Autores: Larrosa Bondia, Francisco Javier|||0000-0002-8322-0505, Meseguer González, Pedro
Tipo de recurso: informe técnico
Fecha de publicación:1997
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/84409
Acceso en línea:https://hdl.handle.net/2117/84409
Access Level:acceso abierto
Palabra clave:Partial forward checking
PFC
Partial lazy forward checking
PLFC
Àrees temàtiques de la UPC::Informàtica::Intel·ligència artificial
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spelling Partial lazy forward checkingLarrosa Bondia, Francisco Javier|||0000-0002-8322-0505Meseguer González, PedroPartial forward checkingPFCPartial lazy forward checkingPLFCÀrees temàtiques de la UPC::Informàtica::Intel·ligència artificialPartial forward checking (PFC) may perform more consistency checks than really needed to detect dead-ends in MAX-CSP. After analyzing PFC, we have identified four causes of redundant check computation: (a) unnecessary lookahead when detecting an empty domain, (b) not always using the better bounds for future value pruning, (c) computing in advance inconsistency counts, and (d) lookahead is performed on the whole set of future variables. We present the partial lazy forward checking (PLFC) algorithm, which follows a lazy approach delaying as much as possible inconsistency count computation, keeping updated the contribution of future variables to the lower bound. This algorithm avoids the causes of redundant checks identified for PFC. It can be easily combined with DACs, producing the PLFC-DAC algorithm. Empirical results on random problems show that PLFC-DAC outperforms previous algorithms in both consistency checks and CPU time.19971997-11-0120162016-03-15reporthttp://purl.org/coar/resource_type/c_93fcVoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/reportapplication/pdfhttps://hdl.handle.net/2117/84409reponame:UPCommons. Portal del coneixement obert de la UPCinstname:Universitat Politècnica de Catalunya (UPC)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:upcommons.upc.edu:2117/844092026-05-27T15:37:01Z
dc.title.none.fl_str_mv Partial lazy forward checking
title Partial lazy forward checking
spellingShingle Partial lazy forward checking
Larrosa Bondia, Francisco Javier|||0000-0002-8322-0505
Partial forward checking
PFC
Partial lazy forward checking
PLFC
Àrees temàtiques de la UPC::Informàtica::Intel·ligència artificial
title_short Partial lazy forward checking
title_full Partial lazy forward checking
title_fullStr Partial lazy forward checking
title_full_unstemmed Partial lazy forward checking
title_sort Partial lazy forward checking
dc.creator.none.fl_str_mv Larrosa Bondia, Francisco Javier|||0000-0002-8322-0505
Meseguer González, Pedro
author Larrosa Bondia, Francisco Javier|||0000-0002-8322-0505
author_facet Larrosa Bondia, Francisco Javier|||0000-0002-8322-0505
Meseguer González, Pedro
author_role author
author2 Meseguer González, Pedro
author2_role author
dc.subject.none.fl_str_mv Partial forward checking
PFC
Partial lazy forward checking
PLFC
Àrees temàtiques de la UPC::Informàtica::Intel·ligència artificial
topic Partial forward checking
PFC
Partial lazy forward checking
PLFC
Àrees temàtiques de la UPC::Informàtica::Intel·ligència artificial
description Partial forward checking (PFC) may perform more consistency checks than really needed to detect dead-ends in MAX-CSP. After analyzing PFC, we have identified four causes of redundant check computation: (a) unnecessary lookahead when detecting an empty domain, (b) not always using the better bounds for future value pruning, (c) computing in advance inconsistency counts, and (d) lookahead is performed on the whole set of future variables. We present the partial lazy forward checking (PLFC) algorithm, which follows a lazy approach delaying as much as possible inconsistency count computation, keeping updated the contribution of future variables to the lower bound. This algorithm avoids the causes of redundant checks identified for PFC. It can be easily combined with DACs, producing the PLFC-DAC algorithm. Empirical results on random problems show that PLFC-DAC outperforms previous algorithms in both consistency checks and CPU time.
publishDate 1997
dc.date.none.fl_str_mv 1997
1997-11-01
2016
2016-03-15
dc.type.none.fl_str_mv report
http://purl.org/coar/resource_type/c_93fc
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/report
format report
dc.identifier.none.fl_str_mv https://hdl.handle.net/2117/84409
url https://hdl.handle.net/2117/84409
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:UPCommons. Portal del coneixement obert de la UPC
instname:Universitat Politècnica de Catalunya (UPC)
instname_str Universitat Politècnica de Catalunya (UPC)
reponame_str UPCommons. Portal del coneixement obert de la UPC
collection UPCommons. Portal del coneixement obert de la UPC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,301603

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