Author: Uri Blass
Date: 13:05:37 03/05/04
Go up one level in this thread
On March 05, 2004 at 14:18:24, Dann Corbit wrote: >On March 05, 2004 at 09:12:39, Mathieu Pagé wrote: > >>On March 04, 2004 at 15:25:53, Dann Corbit wrote: >> >>>On March 04, 2004 at 15:16:43, Mathieu Pagé wrote: >>> >>>>Hi, >>>> >>>>I've just change my minimax algorithm for an AB one. (Yes I know i should have >>>>done this long long time ago, but i did want to keep it simple until it could >>>>play a complete game and understand _all_ the chess rules). >>>> >>>>As expected my engines can search deeper (3-4 more plys) than the old version in >>>>the same time, but the NPS drop dramatically, going from 3.6M nodes/s to a >>>>little bit over 2M nodes/s. It's about 44 % decrease. >>>> >>>>I think it is normal that the nps of Minimax was greater then AB's one because >>>>in AB lot of move are generated, but not searched (so they are not add to the >>>>number of nodes) >>>> >>>>but i think that going from 3.6M to 2M is a big difference. >>>> >>>>Is this behavior normal or did I put an unusual overhead in my algorithm (For >>>>now, i have carefully revised my code and can not see what it is) ? >>>> >>>>TIA :) >>>> >>>>Mathieu Pagé >>> >>>How do you count nodes? >> >>Each call to AB, I count it as a node. (I have no quiescence or other fancy >>things) > >Then I would expect what you are seeing. > >>>Does your perft calculation give a different rate now? >> >>No, my perft is as fast as it was (over 4 millions nodes per seconds) > >I would not worry about it then. > >>>I suspect the difference is that you spend more time in the search and less time >>>in the move generator. But that is only a guess. >> >>I guess you mean more time in the move generation less in the search. did you ? > >No. If you spent more time in the move generator, you would be closer to the 4 >million NPS. You spend more time in the search and call the move generator less >often. That is generally a good thing. You will see the same thing when you >strengthen your evaluation, because it will spend more time in eval and less in >move generation. For an experiment, strap on an evaluation that does nothing >but count wood. Probably, you will see something very high in NPS like one >million and stupendous depth. But it will play like crap. > >>Note that i still have no ordering except a primitive LVA (without MVV ??) move >>ordering is the next step on my TODO > >Hash next. The most important thing for move ordering is hashing, by far. I do not think that it is the most important thing for move ordering. I guess that you get more speed by good captures first and history tables and not by hash after you already have the basic things. I do not know about hash when you have nothing but there are many positions that are not in the hash tables so I do not think that hash alone can be more productive than what tscp does Uri
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