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Created page with "'''Home * Search * Selectivity * Pruning * History Leaf Pruning''' '''History leaf pruning''',<br/> a pruning technique based on History Heuristic..."
'''[[Main Page|Home]] * [[Search]] * [[Selectivity]] * [[Pruning]] * History Leaf Pruning'''
'''History leaf pruning''',<br/>
a pruning technique based on [[History Heuristic|history counters]]. The idea is to prune moves that are <= 0 [[Depth|depth]] after [[Reductions|reductions]] and are below a given history threshold. History Leaf Pruning showed up as an option in [[Fruit|Fruit 05/11/03]] by [[Fabien Letouzey]].
=Sample Code=
<pre>
if (node_type != NodePV) {
if (!in_check && played_nb >= 5 && !extended) {
value = sort->value; // history score
if (value < HistoryThreshold) {
new_depth -= 1;
if (value < LeafThreshold) continue; // History Leaf pruning
reduced = true;
}
}
}
</pre>
=See also=
* [[Bobby#StrategicQuiescenceSearch|Bobby's Strategic Quiescence Search]]
* [[Butterfly Boards]]
* [[Butterfly Heuristic]]
* [[Futility Pruning]]
* [[History Heuristic]]
* [[Late Move Reductions]]
* [[Reductions]]
* [[Relative History Heuristic]]
=Forum Posts=
* [http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=274486&t=28459 Re: Possible search improvment] by [[Ryan Benitez]], [[CCC]], June 17, 2009 » [[ProbCut]]
* [http://www.talkchess.com/forum/viewtopic.php?t=30036 Can someone explain this?] by [[Michel Van den Bergh]], [[CCC]], October 07, 2009 » [[Toga]]
'''[[Pruning|Up one Level]]'''
'''History leaf pruning''',<br/>
a pruning technique based on [[History Heuristic|history counters]]. The idea is to prune moves that are <= 0 [[Depth|depth]] after [[Reductions|reductions]] and are below a given history threshold. History Leaf Pruning showed up as an option in [[Fruit|Fruit 05/11/03]] by [[Fabien Letouzey]].
=Sample Code=
<pre>
if (node_type != NodePV) {
if (!in_check && played_nb >= 5 && !extended) {
value = sort->value; // history score
if (value < HistoryThreshold) {
new_depth -= 1;
if (value < LeafThreshold) continue; // History Leaf pruning
reduced = true;
}
}
}
</pre>
=See also=
* [[Bobby#StrategicQuiescenceSearch|Bobby's Strategic Quiescence Search]]
* [[Butterfly Boards]]
* [[Butterfly Heuristic]]
* [[Futility Pruning]]
* [[History Heuristic]]
* [[Late Move Reductions]]
* [[Reductions]]
* [[Relative History Heuristic]]
=Forum Posts=
* [http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=274486&t=28459 Re: Possible search improvment] by [[Ryan Benitez]], [[CCC]], June 17, 2009 » [[ProbCut]]
* [http://www.talkchess.com/forum/viewtopic.php?t=30036 Can someone explain this?] by [[Michel Van den Bergh]], [[CCC]], October 07, 2009 » [[Toga]]
'''[[Pruning|Up one Level]]'''
