History Leaf Pruning

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History leaf pruning,
a pruning technique based on history counters. The idea is to prune moves that are <= 0 depth after reductions and are below a given history threshold. History Leaf Pruning showed up as an option in Fruit 05/11/03 by Fabien Letouzey.

Sample Code

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;
        }
    }
}

See also

Forum Posts

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