Remove from the search this special case and apply
null search and razoring also in mate positions.
Tested in no-regression mode and passed both
STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 65431 W: 10860 L: 10810 D: 43761
and LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 34928 W: 4814 L: 4713 D: 25401
This patch kicks in only in mate positions and in
these cases it seems beneficial in finding mates
faster as Yery Spark measured on the Chest mate suite:
Total number of positions 6425
Fixed nodes 200K per position
master: 1049
new: 1154
And also the 5446 'hard' positions again with 2000K nodes
(those not found by both engines in 200K nodes):
master: 1069
new: 1395
bench:
7710548
&& depth < 4 * ONE_PLY
&& eval + razor_margin(depth) <= alpha
&& ttMove == MOVE_NONE
&& depth < 4 * ONE_PLY
&& eval + razor_margin(depth) <= alpha
&& ttMove == MOVE_NONE
- && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& !pos.pawn_on_7th(pos.side_to_move()))
{
if ( depth <= ONE_PLY
&& !pos.pawn_on_7th(pos.side_to_move()))
{
if ( depth <= ONE_PLY
&& !ss->skipNullMove
&& depth >= 2 * ONE_PLY
&& eval >= beta
&& !ss->skipNullMove
&& depth >= 2 * ONE_PLY
&& eval >= beta
- && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
{
ss->currentMove = MOVE_NULL;
&& pos.non_pawn_material(pos.side_to_move()))
{
ss->currentMove = MOVE_NULL;
// Null move dynamic reduction based on depth and value
Depth R = 3 * ONE_PLY
+ depth / 4
// Null move dynamic reduction based on depth and value
Depth R = 3 * ONE_PLY
+ depth / 4
- + int(eval - beta) / PawnValueMg * ONE_PLY;
+ + (abs(beta) < VALUE_KNOWN_WIN ? int(eval - beta) / PawnValueMg * ONE_PLY
+ : DEPTH_ZERO);
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
if (nullValue >= VALUE_MATE_IN_MAX_PLY)
nullValue = beta;
if (nullValue >= VALUE_MATE_IN_MAX_PLY)
nullValue = beta;
- if (depth < 12 * ONE_PLY)
+ if (depth < 12 * ONE_PLY && abs(beta) < VALUE_KNOWN_WIN)
return nullValue;
// Do verification search at high depths
return nullValue;
// Do verification search at high depths
singularExtensionNode = !RootNode
&& !SpNode
&& depth >= 8 * ONE_PLY
singularExtensionNode = !RootNode
&& !SpNode
&& depth >= 8 * ONE_PLY
+ && abs(beta) < VALUE_KNOWN_WIN
&& ttMove != MOVE_NONE
&& !excludedMove // Recursive singular search is not allowed
&& (tte->bound() & BOUND_LOWER)
&& ttMove != MOVE_NONE
&& !excludedMove // Recursive singular search is not allowed
&& (tte->bound() & BOUND_LOWER)
if ( singularExtensionNode
&& move == ttMove
&& !ext
if ( singularExtensionNode
&& move == ttMove
&& !ext
- && pos.legal(move, ci.pinned)
- && abs(ttValue) < VALUE_KNOWN_WIN)
+ && pos.legal(move, ci.pinned))
{
assert(ttValue != VALUE_NONE);
{
assert(ttValue != VALUE_NONE);