Double weight of pawn history for quiet move ordering.
I measured on my 1000 position bench the average additional added pawn history per depth.
This shows on average negative value with even smaller values with increaing depth.
A linear regression against depth get following formula:
-1960 - 130 * depth
For compensation add this to the used sort limit to maintain roughly the same proportion of sorted quiet moves.
Remarks:
1. using no compensation failed here https://tests.stockfishchess.org/tests/view/6547664f136acbc5735265f0
2. using only the compensation failed at LTC:
passed STC: https://tests.stockfishchess.org/tests/view/65477457136acbc5735266f8
failed LTC: https://tests.stockfishchess.org/tests/view/65487fc8136acbc573527d1c
STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 98528 W: 25109 L: 24699 D: 48720
Ptnml(0-2): 334, 11586, 25009, 12006, 329
https://tests.stockfishchess.org/tests/view/65475873136acbc5735264f7
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 69726 W: 17467 L: 17073 D: 35186
Ptnml(0-2): 39, 7814, 18769, 8196, 45
https://tests.stockfishchess.org/tests/view/6547e759136acbc573527071
closes https://github.com/official-stockfish/Stockfish/pull/4866
Bench: 1379422