i’m now within 100 elo of my target, but it’s still not looking great.

it seems i have hit another wall. there’s this copypasta around chess programming circles with a rough order of search features to implement, and i’ve tried 3 in a row, none doing much.

since last time, i’ve just added two things that have gained elo:

• history decay tweak (10 elo): after searching a position, decay history by 50% instead of 80%, helps retain memory from previous searches
• check extensions (23 elo): extend a search by 1 more move if in check. it’s very simple.

i’ve since tried IIR (internal iterative reductions), SEE pruning in PVS (more moveloop pruning), and continuation history (like the history heuristic, but More™️). only continuation history has kinda done something, but only when comparing against a version that’s just as slow; when comparing against the original, it’s much closer because for some reason continuation history slows down the search by almost 10% (??????). The main slow-down-er seems to be indexing the continuation history array, which is absolutely baffling to me. i’ve even tried to start reading the GHC Core again, until i remembered why it was so painful last time.