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Incremental Futility Margin

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Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-11-14 21:36:43 +01:00
parent 989833205f
commit 0eedf47661
1 changed files with 11 additions and 5 deletions
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16
src/search.cpp
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@ -176,6 +176,9 @@ namespace {
// and near frontier nodes. // and near frontier nodes.
const Value FutilityMarginQS = Value(0x80); const Value FutilityMarginQS = Value(0x80);
// Each move futility margin is decreased
const Value IncrementalFutilityMargin = Value(0xA);
// Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270), const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270),
// 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply // 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply
@ -1260,7 +1263,7 @@ namespace {
const TTEntry* tte; const TTEntry* tte;
Move ttMove, move; Move ttMove, move;
Depth ext, newDepth; Depth ext, newDepth;
Value approximateEval, nullValue, value, futilityValue; Value approximateEval, nullValue, value, futilityValue, futilityValueScaled;
bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous; bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false; bool mateThreat = false;
int moveCount = 0; int moveCount = 0;
@ -1420,12 +1423,15 @@ namespace {
{ {
if (futilityValue == VALUE_NONE) if (futilityValue == VALUE_NONE)
futilityValue = evaluate(pos, ei, threadID) futilityValue = evaluate(pos, ei, threadID)
+ FutilityMargins[int(depth) - 2]; + FutilityMargins[int(depth) - 2]
+ 4*IncrementalFutilityMargin;
if (futilityValue < beta) futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
if (futilityValueScaled < beta)
{ {
if (futilityValue > bestValue) if (futilityValueScaled > bestValue)
bestValue = futilityValue; bestValue = futilityValueScaled;
continue; continue;
} }
} }