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Code Issues Releases Wiki Activity

Further simplify aspiration code

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Actually after last patch it happens that delta
starts always with the fixed value of 16.

So further remove useless code.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2011-12-14 06:18:33 +01:00
parent 96213689e4
commit 852d45a600
1 changed files with 12 additions and 15 deletions
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27
src/search.cpp
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@ -426,8 +426,8 @@ namespace {
Stack ss[PLY_MAX_PLUS_2]; Stack ss[PLY_MAX_PLUS_2];
int bestMoveChanges[PLY_MAX_PLUS_2]; int bestMoveChanges[PLY_MAX_PLUS_2];
int depth, delta; int depth;
Value bestValue, alpha, beta; Value bestValue, alpha, beta, delta;
Move bestMove, skillBest, skillPonder; Move bestMove, skillBest, skillPonder;
bool bestMoveNeverChanged = true; bool bestMoveNeverChanged = true;
@ -436,8 +436,8 @@ namespace {
H.clear(); H.clear();
RootMoves.clear(); RootMoves.clear();
*ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE; *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE;
depth = delta = 0; depth = 0;
bestValue = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE; bestValue = alpha = -VALUE_INFINITE, beta = delta = VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update gains ss->currentMove = MOVE_NULL; // Hack to skip update gains
for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml) for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
@ -467,16 +467,11 @@ namespace {
for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, RootMoves.size()); MultiPVIdx++) for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, RootMoves.size()); MultiPVIdx++)
{ {
// Calculate dynamic aspiration window based on previous iteration // Calculate dynamic aspiration window based on previous iteration
if (depth >= 5 && abs(RootMoves[MultiPVIdx].score) < VALUE_KNOWN_WIN) if (depth >= 5 && abs(RootMoves[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN)
{ {
delta = abs(RootMoves[MultiPVIdx].score - RootMoves[MultiPVIdx].prevScore); delta = Value(16);
delta = std::min(std::max(delta, 16), 24); alpha = RootMoves[MultiPVIdx].prevScore - delta;
delta = (delta + 7) / 8 * 8; // Round to match grainSize beta = RootMoves[MultiPVIdx].prevScore + delta;
alpha = RootMoves[MultiPVIdx].score - delta;
beta = RootMoves[MultiPVIdx].score + delta;
assert(alpha > -VALUE_INFINITE && beta < VALUE_INFINITE);
} }
else else
{ {
@ -544,7 +539,7 @@ namespace {
// research, otherwise exit the fail high/low loop. // research, otherwise exit the fail high/low loop.
if (bestValue >= beta) if (bestValue >= beta)
{ {
beta = std::min(beta + delta, VALUE_INFINITE); beta += delta;
delta += delta / 2; delta += delta / 2;
} }
else if (bestValue <= alpha) else if (bestValue <= alpha)
@ -552,12 +547,14 @@ namespace {
Signals.failedLowAtRoot = true; Signals.failedLowAtRoot = true;
Signals.stopOnPonderhit = false; Signals.stopOnPonderhit = false;
alpha = std::max(alpha - delta, -VALUE_INFINITE); alpha -= delta;
delta += delta / 2; delta += delta / 2;
} }
else else
break; break;
assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
} while (abs(bestValue) < VALUE_KNOWN_WIN); } while (abs(bestValue) < VALUE_KNOWN_WIN);
} }