Revert 5 patches which were merged, but lead to a regression test that showed negative Elo gain:
http://tests.stockfishchess.org/tests/view/
5e307251ab2d69d58394fdb9
This was discussed in depth in:
https://github.com/official-stockfish/Stockfish/issues/2531
Each patch was removed and tested as a simplification, full list below, and the whole combo as well.
After the revert the regression test showed a neutral result:
http://tests.stockfishchess.org/tests/view/
5e334851708b13464ceea33c
As a result of this experience, the SPRT testing bounds will be made more strict.
Reverted patches:
1 Dynamic Complexity
6d0eabd5fe2961551477820ab7619e2c31e01ffd :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/
5e31fcacec661e2e6a340d08 :
LLR: 2.97 (-2.94,2.94) {-1.50,0.50}
Total: 38130 W: 7326 L: 7189 D: 23615
Ptnml(0-2): 677, 4346, 8843, 4545, 646
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/
5e32c18fec661e2e6a340d73 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 38675 W: 4941 L: 4866 D: 28868
Ptnml(0-2): 270, 3556, 11429, 3584, 291
3 More bonus for bestMoves on past PV nodes
71e0b5385e2717679a57c6b77d8c7ac5fff3b89f :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/
5e31fe93ec661e2e6a340d10 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 46100 W: 8853 L: 8727 D: 28520
Ptnml(0-2): 796, 5297, 10749, 5387, 813
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/
5e32c187ec661e2e6a340d71 :
LLR: 2.96 (-2.94,2.94) {-1.50,0.50}
Total: 16920 W: 2161 L: 2055 D: 12704
Ptnml(0-2): 115, 1498, 5006, 1569, 130
4 Tweak Restricted Piece Bonus
0ae00454ba6928d181b46103e5c83e6d58fcebe5 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/
5e31fefaec661e2e6a340d15 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 88328 W: 17060 L: 16997 D: 54271
Ptnml(0-2): 1536, 10446, 20169, 10422, 1581
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/
5e32c17aec661e2e6a340d6f :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 34784 W: 4551 L: 4466 D: 25767
Ptnml(0-2): 255, 3279, 10061, 3345, 262
5 History update for pruned captures
01b6088af39902001d2d6844561b6a2faa549282 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/
5e31ff5eec661e2e6a340d1a :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 29541 W: 5735 L: 5588 D: 18218
Ptnml(0-2): 483, 3445, 6820, 3469, 545
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/
5e32c196ec661e2e6a340d75 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 22177 W: 2854 L: 2757 D: 16566
Ptnml(0-2): 143, 2005, 6555, 2055, 164
6 Tweak trapped rook penalty
18fc21eba0368fd5e3c4c4b8ee1000c9ac445425 :
STC 10+0.1 https://tests.stockfishchess.org/tests/view/
5e31ffb1ec661e2e6a340d1c :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 24476 W: 4727 L: 4569 D: 15180
Ptnml(0-2): 390, 2834, 5659, 2933, 417
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/
5e32c19eec661e2e6a340d77 :
LLR: 2.95 (-2.94,2.94) {-1.50,0.50}
Total: 97332 W: 12492 L: 12466 D: 72374
Ptnml(0-2): 690, 9107, 28738, 9034, 720
All 5 as one simplification :
LTC 60+0.6 https://tests.stockfishchess.org/tests/view/
5e334098708b13464ceea330 :
LLR: 2.94 (-2.94,2.94) {-1.50,0.50}
Total: 7829 W: 1079 L: 964 D: 5786
Ptnml(0-2): 52, 690, 2281, 781, 65
Bench:
5153165
constexpr Score ThreatByKing = S( 24, 89);
constexpr Score ThreatByPawnPush = S( 48, 39);
constexpr Score ThreatBySafePawn = S(173, 94);
- constexpr Score TrappedRook = S( 52, 30);
+ constexpr Score TrappedRook = S( 52, 10);
constexpr Score WeakQueen = S( 49, 15);
#undef S
b = attackedBy[Them][ALL_PIECES]
& ~stronglyProtected
& attackedBy[Us][ALL_PIECES];
- score += RestrictedPiece * (popcount(b) + popcount(b & pos.pieces()));
+ score += RestrictedPiece * popcount(b);
// Protected or unattacked squares
safe = ~attackedBy[Them][ALL_PIECES] | attackedBy[Us][ALL_PIECES];
- 100 ;
// Give more importance to non-material score
- score = score - pos.psq_score() / 2;
Value mg = mg_value(score);
Value eg = eg_value(score);
void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus);
void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus);
void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq,
- Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth, bool pastPV);
+ Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth);
// perft() is our utility to verify move generation. All the leaf nodes up
// to the given depth are generated and counted, and the sum is returned.
if (ttValue >= beta)
{
if (!pos.capture_or_promotion(ttMove))
- update_quiet_stats(pos, ss, ttMove, stat_bonus(depth + (!PvNode && ttPv)));
+ update_quiet_stats(pos, ss, ttMove, stat_bonus(depth));
// Extra penalty for early quiet moves of the previous ply
if ((ss-1)->moveCount <= 2 && !priorCapture)
// Penalty for a quiet ttMove that fails low
else if (!pos.capture_or_promotion(ttMove))
{
- int penalty = -stat_bonus(depth + (!PvNode && ttPv));
+ int penalty = -stat_bonus(depth);
thisThread->mainHistory[us][from_to(ttMove)] << penalty;
update_continuation_histories(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
}
continue;
}
else if (!pos.see_ge(move, Value(-194) * depth)) // (~25 Elo)
- {
- if (captureOrPromotion && captureCount < 32)
- capturesSearched[captureCount++] = move;
continue;
- }
}
// Step 14. Extensions (~75 Elo)
else if (bestMove)
update_all_stats(pos, ss, bestMove, bestValue, beta, prevSq,
- quietsSearched, quietCount, capturesSearched, captureCount, depth, (!PvNode && ttPv));
+ quietsSearched, quietCount, capturesSearched, captureCount, depth);
// Bonus for prior countermove that caused the fail low
else if ( (depth >= 3 || PvNode)
// update_all_stats() updates stats at the end of search() when a bestMove is found
void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq,
- Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth, bool pastPV) {
+ Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth) {
int bonus1, bonus2;
Color us = pos.side_to_move();
PieceType captured = type_of(pos.piece_on(to_sq(bestMove)));
bonus1 = stat_bonus(depth + 1);
- bonus2 = pastPV || bestValue > beta + PawnValueMg ? bonus1 // larger bonus
- : stat_bonus(depth); // smaller bonus
+ bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus
+ : stat_bonus(depth); // smaller bonus
if (!pos.capture_or_promotion(bestMove))
{