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Revert "null move reorder" series

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Does not seem to improve on the standard, latest results
from Joona after 2040 games are negative:

Orig - Mod: 454 - 424 - 1162

And is more or less the same I got few days ago.

So revert for now.

Verified same functionality of 595a90dfd

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2009-08-29 20:19:09 +01:00
parent 9ab84a8165
commit e9de96f0e4
3 changed files with 54 additions and 72 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/search.cpp
+50 -56
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@@ -1281,21 +1281,57 @@ namespace {
bool mateThreat = false;
bool isCheck = pos.is_check();
bool useNullMove = ( allowNullmove
&& depth > OnePly
&& !isCheck
&& !value_is_mate(beta)
&& ok_to_do_nullmove(pos)
&& approximateEval >= beta - NullMoveMargin);
// Null move search
if ( allowNullmove
&& depth > OnePly
&& !isCheck
&& !value_is_mate(beta)
&& ok_to_do_nullmove(pos)
&& approximateEval >= beta - NullMoveMargin)
{
ss[ply].currentMove = MOVE_NULL;
StateInfo st;
pos.do_null_move(st);
int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move();
if (nullValue >= beta)
{
if (depth < 6 * OnePly)
return beta;
// Do zugzwang verification search
Value v = search(pos, ss, beta, depth-5*OnePly, ply, false, threadID);
if (v >= beta)
return beta;
} else {
// The null move failed low, which means that we may be faced with
// some kind of threat. If the previous move was reduced, check if
// the move that refuted the null move was somehow connected to the
// move which was reduced. If a connection is found, return a fail
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
if (nullValue == value_mated_in(ply + 2))
mateThreat = true;
ss[ply].threatMove = ss[ply + 1].currentMove;
if ( depth < ThreatDepth
&& ss[ply - 1].reduction
&& connected_moves(pos, ss[ply - 1].currentMove, ss[ply].threatMove))
return beta - 1;
}
}
// Null move search not allowed, try razoring
if ( !useNullMove
&& !value_is_mate(beta)
&& depth < RazorDepth
&& approximateEval < beta - RazorApprMargins[int(depth) - 2]
&& ss[ply - 1].currentMove != MOVE_NULL
&& ttMove == MOVE_NONE
&& !pos.has_pawn_on_7th(pos.side_to_move()))
else if ( !value_is_mate(beta)
&& depth < RazorDepth
&& approximateEval < beta - RazorApprMargins[int(depth) - 2]
&& ss[ply - 1].currentMove != MOVE_NULL
&& ttMove == MOVE_NONE
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
if (v < beta - RazorMargins[int(depth) - 2])
@@ -1312,7 +1348,7 @@ namespace {
// Initialize a MovePicker object for the current position, and prepare
// to search all moves.
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply], useNullMove);
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
Move move, movesSearched[256];
int moveCount = 0;
@@ -1328,48 +1364,6 @@ namespace {
&& (move = mp.get_next_move()) != MOVE_NONE
&& !thread_should_stop(threadID))
{
// Null move search
if (move == MOVE_NULL)
{
ss[ply].currentMove = MOVE_NULL;
StateInfo st;
pos.do_null_move(st);
int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move();
if (nullValue >= beta)
{
if (depth < 6 * OnePly)
return beta;
// Do zugzwang verification search
Value v = search(pos, ss, beta, depth-5*OnePly, ply, false, threadID);
if (v >= beta)
return beta;
} else {
// The null move failed low, which means that we may be faced with
// some kind of threat. If the previous move was reduced, check if
// the move that refuted the null move was somehow connected to the
// move which was reduced. If a connection is found, return a fail
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
if (nullValue == value_mated_in(ply + 2))
mateThreat = true;
ss[ply].threatMove = ss[ply + 1].currentMove;
if ( depth < ThreatDepth
&& ss[ply - 1].reduction
&& connected_moves(pos, ss[ply - 1].currentMove, ss[ply].threatMove))
return beta - 1;
}
continue;
}
assert(move_is_ok(move));
bool singleReply = (isCheck && mp.number_of_moves() == 1);