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That really sounds like a make move error to me, zobrist collision with that amount of nodes is unlikely to occur that often edit: For debugging purposes, you can try to make zobrist keys static, or start from a fixed seed. This makes it easier to find the error, just perft_div until you found the i...

Am I correct that I should be trying to read just before board.gen_all_moves(mlp.get_list_mut(index)); Then, if I find anything, just return the stored number of leaf nodes and if I don't find anything, do the normal perft routine, and store the position just before passing back the number of leaf ...

Trying to recreate my post from earlier: You will want to have O(1) when reading from the hashtable, instead of a linear search for each key. So in Rust, I would do: let mut hash_table = vec![HashEntry::default(); HASH_SIZE]; pub fn insert_entry(hash_table: &mut Vec<HashEntry>, entry: HashEntry){ le...

Posting lost due to moderator stupidity.

Sorry about that, HGM.

edit: this evening I wrote a function to execute all the perft tests in "perftsuite.epd" as posted here (many other engines and authors include it, by the way): https://github.com/TerjeKir/Chess-test-suites/blob/master/EPDs/perftsuite.epd It verified all 127 positions without errors. Many things in...

Why should that be necessary? Because the hashtable won't work with that many threads and exclusive access. The engine would spend all of its time waiting for the access right to be passed around. Splitting the hashtable into exclusive per-thread chunks won't work either because the hashtable is wh...

Personally, I think using unsafe code to intentionally do something which the core language specifically prohibits, is uglier than writing a "workaround" like a move list pool. Using pools, be it for threads, applications, or stuff like printers, is a known way to share resources. I for myself can ...

I think the difference to C is that stack variables are not zero initialised in C. Of course it's going to be slow if you have some zeroing loop going on for 256 elements even if it turns out that you only have 20 moves, like in the initial position itself. So the question would be how to get unini...

Here is a pretty good list: https://github.com/elcabesa/vajolet/blo ... /perft.txt

Also: https://github.com/zd3nik/aperft/blob/m ... tsuite.epd

You should read in a file of perft test positions and run more tests, you will wonder about all the rules in chess you missed. There are pretty exhaustive lists out on talkchess. There even were some things I missed and only fixed some months after the engines was already listed on rating lists, wit...