Author: Bas Hamstra
Date: 06:17:59 06/01/00
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On May 31, 2000 at 19:24:37, Brian Richardson wrote: >On May 31, 2000 at 18:02:42, Bas Hamstra wrote: > >>Tom, >> >>I read another thread about Killers and have an opinion on it. >> >>- Doing captures separately speeds you up considerably >>- Doing an on the fly legality check for killers speeds you up noticably >>- Doing SEE based pruning of losing captures in the qsearch cuts the number of >>nodes and improves node/qnode ratio. You don't have to SEE sort for it. I doubt >>SEE sorting is a winner anyway. >>- Having the former, you can skip losing captures in the normal search as well >>with it, and do those later. Improves sorting noticably. >> >>This goes for all versions and half baken versions I have ever made. >> >>Bas. > >I did some quick tests with Tinker (of course, the search "ecosystem" of each >program will be very different). Normally, Tinker probes the hash table, then >does the hash move (if any), then killers, then generates moves, and so on. I hope you DO captures before killers? Doing that, killers should be a big win. But note that if you already do history, that the extra gain of killers is far less, because both try to achieve the same. >For the following, one history table for both sides is always used. Tested on >five positions (opening, two from WAC, one from Fine and one BT2630): >1) Turning hash moves off--usually 2x slower, up to 10x slower, one test 5% >faster. >2) Turning killers off (keeping 2 moves)--very mixed results: same, or up to 30% >faster or up to 10x slower (Fine16) This 10x slower is counter intuitive to me. If you don't use history sorting killers should be a big win. If you do, it is a small win overall. >3) Turning off both--better than no killers, but worse than no hash move. > >To my surprise, Tinker's WAC 300 score went UP with no killers. Again, this is >with history (disabling history slows everything down A LOT). I may try some >self-play tests with and without killers. > >Brian Richardson Maybe you could also include: a) History and no killers and b) Killers and no history? I suspect that if you already use 2 killers the gain of adding history is small. And since killers are cheaper I don't use history sorting... Regards, Bas.
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