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Add extra bonus to pawn history for a move that caused a fail low

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Basically the same idea as it is for continuation/main history, but it
has some tweaks.
1) it has * 2 multiplier for bonus instead of full/half bonus - for
   whatever reason this seems to work better;
2) attempts with this type of big bonuses scaled somewhat poorly (or
   were unlucky at longer time controls), but after measuring the fact
   that average value of pawn history in LMR after adding this bonuses
   increased by substantial number (for multiplier 1,5 it increased by
   smth like 400~ from 8192 cap) attempts were made to make default pawn
   history negative to compensate it - and version with multiplier 2 and
   initial fill value -900 passed.

Passed STC:
https://tests.stockfishchess.org/tests/view/66424815f9f4e8fc783cba59
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 115008 W: 30001 L: 29564 D: 55443
Ptnml(0-2): 432, 13629, 28903, 14150, 390

Passed LTC:
https://tests.stockfishchess.org/tests/view/6642f5437134c82f3f7a3ffa
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 56448 W: 14432 L: 14067 D: 27949
Ptnml(0-2): 36, 6268, 15254, 6627, 39

Bench: 1857237
This commit is contained in:
Michael Chaly 2024-05-14 20:10:01 +03:00 • committed by Disservin
parent fa114266fa
commit 9e45644c50
1 changed files with 6 additions and 1 deletions
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7
src/search.cpp
View file

@ -496,7 +496,7 @@ void Search::Worker::clear() {
counterMoves.fill(Move::none());
mainHistory.fill(0);
captureHistory.fill(0);
pawnHistory.fill(0);
pawnHistory.fill(-900);
correctionHistory.fill(0);
for (bool inCheck : {false, true})
@ -1335,6 +1335,11 @@ moves_loop: // When in check, search starts here
stat_bonus(depth) * bonus);
thisThread->mainHistory[~us][((ss - 1)->currentMove).from_to()]
<< stat_bonus(depth) * bonus / 2;
if (type_of(pos.piece_on(prevSq)) != PAWN && ((ss - 1)->currentMove).type_of() != PROMOTION)
thisThread->pawnHistory[pawn_structure_index(pos)][pos.piece_on(prevSq)][prevSq]
<< stat_bonus(depth) * bonus * 2;
}
if (PvNode)