25,161
edits
Changes
Created page with "'''Home * Search * Selectivity * Extensions * PV Extensions''' '''PV Extensions''', (PVS Extensions) a technique to extend along the Principal var..."
'''[[Main Page|Home]] * [[Search]] * [[Selectivity]] * [[Extensions]] * PV Extensions'''
'''PV Extensions''', (PVS Extensions)
a technique to extend along the [[Principal variation|principal variation]] (PV) to achieve higher [[Depth|search depths]] in the critical part of the [[Search Tree|tree]]. In [[Rebel]], [[Ed Schroder|Ed Schröder]] incremented a counter each time two consecutive [[PV-Move|PV-moves]] were retrieved from the [[Transposition Table|transposition table]], to extend by one [[Ply|ply]] each time the counter is divisible by four <ref>[http://www.top-5000.nl/authors/rebel/chess840.htm#PVS Extension Techniques in REBEL (PVS extensions)] from [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner] by [[Ed Schroder|Ed Schröder]]</ref>. <span id="Multiple"></span>Influenced by observing the principal variations of [[Junior]] during the [[Kasparov versus Deep Junior 2003]] match, [[David Levy]] proposed multiple extensions to treat the often early stable part of a PV as a single ply in 2003 <ref>[[David Levy]] ('''2003'''). ''The State of the Art in Man vs. “Machine” Chess''. [[ICGA Journal]], Vol. 26, No. 1</ref>. To determine the length of the PV, Levy expresses a threshold as a percentage of the total number of nodes searched with the common PV during the previous iteration of the [[Iterative Deepening|iterative deepening]].
=See also=
* [[Late Move Reductions]]
* [[SEX Algorithm]]
* [[Singular Extensions]]
=Publications=
* [[David Levy]] ('''2003'''). ''The State of the Art in Man vs. “Machine” Chess''. [[ICGA Journal]], Vol. 26, No. 1
=Forum Posts=
* [https://www.stmintz.com/ccc/index.php?id=74 PV verification heuristic] by Peter Jacobi, [[CCC]], July 05, 1998
* [https://www.stmintz.com/ccc/index.php?id=21808 Re: PV verification heuristic] by [[Robert Hyatt]], [[CCC]], July 06, 1998
* [http://www.talkchess.com/forum/viewtopic.php?t=15216 @Ed about PV extension] by [[Peter Fendrich]], [[CCC]], July 19, 2007
=External Links=
* [http://www.top-5000.nl/authors/rebel/chess840.htm#PVS Extension Techniques in REBEL (PVS extensions)] from [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner] by [[Ed Schroder|Ed Schröder]] <ref>How Rebel Plays Chess as [http://members.home.nl/matador/Inside%20Rebel.pdf pdf reprint]</ref>
=References=
<references />
'''[[Extensions|Up one level]]'''
'''PV Extensions''', (PVS Extensions)
a technique to extend along the [[Principal variation|principal variation]] (PV) to achieve higher [[Depth|search depths]] in the critical part of the [[Search Tree|tree]]. In [[Rebel]], [[Ed Schroder|Ed Schröder]] incremented a counter each time two consecutive [[PV-Move|PV-moves]] were retrieved from the [[Transposition Table|transposition table]], to extend by one [[Ply|ply]] each time the counter is divisible by four <ref>[http://www.top-5000.nl/authors/rebel/chess840.htm#PVS Extension Techniques in REBEL (PVS extensions)] from [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner] by [[Ed Schroder|Ed Schröder]]</ref>. <span id="Multiple"></span>Influenced by observing the principal variations of [[Junior]] during the [[Kasparov versus Deep Junior 2003]] match, [[David Levy]] proposed multiple extensions to treat the often early stable part of a PV as a single ply in 2003 <ref>[[David Levy]] ('''2003'''). ''The State of the Art in Man vs. “Machine” Chess''. [[ICGA Journal]], Vol. 26, No. 1</ref>. To determine the length of the PV, Levy expresses a threshold as a percentage of the total number of nodes searched with the common PV during the previous iteration of the [[Iterative Deepening|iterative deepening]].
=See also=
* [[Late Move Reductions]]
* [[SEX Algorithm]]
* [[Singular Extensions]]
=Publications=
* [[David Levy]] ('''2003'''). ''The State of the Art in Man vs. “Machine” Chess''. [[ICGA Journal]], Vol. 26, No. 1
=Forum Posts=
* [https://www.stmintz.com/ccc/index.php?id=74 PV verification heuristic] by Peter Jacobi, [[CCC]], July 05, 1998
* [https://www.stmintz.com/ccc/index.php?id=21808 Re: PV verification heuristic] by [[Robert Hyatt]], [[CCC]], July 06, 1998
* [http://www.talkchess.com/forum/viewtopic.php?t=15216 @Ed about PV extension] by [[Peter Fendrich]], [[CCC]], July 19, 2007
=External Links=
* [http://www.top-5000.nl/authors/rebel/chess840.htm#PVS Extension Techniques in REBEL (PVS extensions)] from [http://www.top-5000.nl/authors/rebel/chess840.htm Programmer Corner] by [[Ed Schroder|Ed Schröder]] <ref>How Rebel Plays Chess as [http://members.home.nl/matador/Inside%20Rebel.pdf pdf reprint]</ref>
=References=
<references />
'''[[Extensions|Up one level]]'''
