gab8192 49ef4c935a Implement accumulator refresh table ... For each thread persist an accumulator cache for the network, where each cache contains multiple entries for each of the possible king squares. When the accumulator needs to be refreshed, the cached entry is used to more efficiently update the accumulator, instead of rebuilding it from scratch. This idea, was first described by Luecx (author of Koivisto) and is commonly referred to as "Finny Tables". When the accumulator needs to be refreshed, instead of filling it with biases and adding every piece from scratch, we... 1. Take the `AccumulatorRefreshEntry` associated with the new king bucket 2. Calculate the features to activate and deactivate (from differences between bitboards in the entry and bitboards of the actual position) 3. Apply the updates on the refresh entry 4. Copy the content of the refresh entry accumulator to the accumulator we were refreshing 5. Copy the bitboards from the position to the refresh entry, to match the newly updated accumulator Results at STC: https://tests.stockfishchess.org/tests/view/662301573fe04ce4cefc1386 (first version) https://tests.stockfishchess.org/tests/view/6627fa063fe04ce4cefc6560 (final) Non-Regression between first and final: https://tests.stockfishchess.org/tests/view/662801e33fe04ce4cefc660a STC SMP: https://tests.stockfishchess.org/tests/view/662808133fe04ce4cefc667c closes https://github.com/official-stockfish/Stockfish/pull/5183 No functional change		2024-04-24 18:38:20 +02:00
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half_ka_v2_hm.cpp	Implement accumulator refresh table	2024-04-24 18:38:20 +02:00
half_ka_v2_hm.h	Implement accumulator refresh table	2024-04-24 18:38:20 +02:00