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Simplify "easy move" detection

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Detect a move as easy only if it is the only one ;-)
or if is much better than remaining ones after we
have spent 20% of search time.

Tests are ongoing, but it seems this semplification
stands. Anyhow it is experimental for now and could
be reverted/improved with further work Gary is
testing right now.

No functional change.
This commit is contained in:
Marco Costalba
2013-03-04 09:27:00 +01:00
parent ccad601389
commit 45dba12c5b
1 changed files with 2 additions and 13 deletions
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15
src/search.cpp
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@@ -294,7 +294,6 @@ namespace {
Stack ss[MAX_PLY_PLUS_2]; Stack ss[MAX_PLY_PLUS_2];
int depth, prevBestMoveChanges; int depth, prevBestMoveChanges;
Value bestValue, alpha, beta, delta; Value bestValue, alpha, beta, delta;
bool bestMoveNeverChanged = true;
memset(ss, 0, 4 * sizeof(Stack)); memset(ss, 0, 4 * sizeof(Stack));
depth = BestMoveChanges = 0; depth = BestMoveChanges = 0;
@@ -417,10 +416,6 @@ namespace {
<< std::endl; << std::endl;
} }
// Filter out startup noise when monitoring best move stability
if (depth > 2 && BestMoveChanges)
bestMoveNeverChanged = false;
// Do we have found a "mate in x"? // Do we have found a "mate in x"?
if ( Limits.mate if ( Limits.mate
&& bestValue >= VALUE_MATE_IN_MAX_PLY && bestValue >= VALUE_MATE_IN_MAX_PLY
@@ -442,18 +437,12 @@ namespace {
if (Time::now() - SearchTime > (TimeMgr.available_time() * 62) / 100) if (Time::now() - SearchTime > (TimeMgr.available_time() * 62) / 100)
stop = true; stop = true;
bool recapture = pos.is_capture(RootMoves[0].pv[0])
&& pos.captured_piece_type()
&& SetupMoves->size()
&& to_sq(SetupMoves->back()) == to_sq(RootMoves[0].pv[0]);
// Stop search early if one move seems to be much better than others // Stop search early if one move seems to be much better than others
if ( depth >= 12 if ( depth >= 12
&& !stop && !stop
&& PVSize == 1 && PVSize == 1
&& ( (bestMoveNeverChanged && recapture) && ( RootMoves.size() == 1
|| RootMoves.size() == 1 || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100))
|| Time::now() - SearchTime > (TimeMgr.available_time() * 40) / 100))
{ {
Value rBeta = bestValue - 2 * PawnValueMg; Value rBeta = bestValue - 2 * PawnValueMg;
(ss+1)->excludedMove = RootMoves[0].pv[0]; (ss+1)->excludedMove = RootMoves[0].pv[0];