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Retire EasyMoveMargin 

Use a value related to PawnValue instead.

This is a different patch from previous one because
could affect game play and skill levels, although
in a mostly unmeasurable way. Indeed thresold has
been raised so easy move is a bit harder to trigger
and skill level is a bit more prone to blunders.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
sf_3_base
Marco Costalba 2012-10-03 10:34:42 +02:00
parent 561eb34aea
commit bd7a0d4ce4
1 changed files with 2 additions and 6 deletions
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8
src/search.cpp
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@ -88,10 +88,6 @@ namespace {
return (Depth) Reductions[PvNode][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
// Easy move margin. An easy move candidate must be at least this much better
// than the second best move.
const Value EasyMoveMargin = Value(0x150);
// This is the minimum interval in msec between two check_time() calls
const int TimerResolution = 5;
@ -450,7 +446,7 @@ namespace {
&& ( (bestMoveNeverChanged && pos.captured_piece_type())
|| Time::now() - SearchTime > (TimeMgr.available_time() * 40) / 100))
{
Value rBeta = bestValue - EasyMoveMargin;
Value rBeta = bestValue - 2 * PawnValueMg;
(ss+1)->excludedMove = RootMoves[0].pv[0];
(ss+1)->skipNullMove = true;
Value v = search<NonPV>(pos, ss+1, rBeta - 1, rBeta, (depth - 3) * ONE_PLY);
@ -1494,7 +1490,7 @@ split_point_start: // At split points actual search starts from here
int s = RootMoves[i].score;
// Don't allow crazy blunders even at very low skills
if (i > 0 && RootMoves[i-1].score > s + EasyMoveMargin)
if (i > 0 && RootMoves[i-1].score > s + 2 * PawnValueMg)
break;
// This is our magic formula