Improve Accumulator Update Heuristics

Description

When doing incremental updates, at most two accumluators are updated: one for the current position and the other for the position following the last computed accumulator. Try different heuristics and see if they yield speedups.

Branches

• 38e0cc7b-4

Tests

Test #1

Stockfish Testing Framework

Result

Stopped

Stats

LLR: -0.30 (-2.94,2.94) <0.00,2.00>
Total: 5920 W: 1505 L: 1523 D: 2892
Ptnml(0-2): 12, 693, 1580, 651, 24

The default bench has shown 2% speedup; however, no speedup was observed in depth 24 bench. The test was stopped after reviewing the results from the depth 24 bench.