Author: Peter McKenzie
Date: 17:09:06 05/01/00
Go up one level in this thread
On May 01, 2000 at 18:50:24, Robert Hyatt wrote: >On April 30, 2000 at 22:34:17, Christophe Theron wrote: > >>On April 30, 2000 at 18:42:57, Amir Ban wrote: >> >>>On April 30, 2000 at 16:39:04, Christophe Theron wrote: >>> >>>>On April 30, 2000 at 06:47:29, Amir Ban wrote: >>>> >>>>>On April 29, 2000 at 11:31:09, Eran wrote: >>>>> >>>>>> >>>>>>I am sorry if I said it. Okay I believe you that Junior6 has underpromotion code >>>>>>and that's wonderful. Maybe I will consider buying it. Does Junior6 consume >>>>>>hashtable memory as large as fritz does? Is having large hashtable memory >>>>>>important for Junior6? Is 40 MB hashtable enough for 40/120 games? >>>>>> >>>>>>Eran >>>>> >>>>>More memory for hash is good, but Junior is not very sensitive to it and you can >>>>>change memory size by order of magnitude without obvious effect on playing >>>>>strength. >>>>> >>>>>The comparison to Fritz is interesting and backward: I believe that Fritz 6 >>>>>(new) consumes less memory than previous versions and the reason may be a >>>>>conversation I had with Frans about this in Paderborn, from which he may have >>>>>decided that he doesn't need so much memory. >>>>> >>>>>Amir >>>> >>>> >>>> >>>>I must admit I don't understand what you say... >>>> >>>> >>>> Christophe >>> >>> >>>Then why don't you ask :) >>> >>>I understood from Frans that he's hashing quiescence nodes. I told him I don't, >>>and that I consider it a waste of time. >>> >>>Amir >> >> >> >>I hash quies nodes. I tried both methods (hashing them and not hashing them) and >>found that hashing QSearch nodes was definitely better, but not by much. I did >>hours of experiments and drew a lot of curves with my spreadsheet in order to >>find this. >> >>It works better even if the hash table is highly saturated. >> >>That's how it works for me. I don't think that I have a better hashing/replacing >>strategy, actually it is rather simplistic. Maybe it's because I do more in >>QSearch than both of you do, although I cannot know for sure. >> >>Maybe I should check again... :) >> >> >> >> Christophe > > >I used to hash q-search nodes. I found it reduced the size of the tree by about >10%. I also found that by taking it out, I reduced the total search time by >15 %. A net gain of 5%. More importantly, I don't need nearly the hash memory >now since over half of the search is not hashed. I can't remember for certain, but I think I do hash the q-search. Like Christophe/Tiger (but unlike Crafty), I do a bit more that just the minimal q-search, so perhaps this is what makes hashing those nodes worthwhile for our programs. > >My next task is to save some time by getting rid of the hashing/unhashing code >in the q-search as well, since it isn't used... I assume you are talking about updating the hash key? Surely this is a tiny overhead, but it all adds up I guess. I wonder if the speedup (if any) will offset the added complexity in your make/unmake functions, or do you plan to create new versions of make/unmake? Sounds like you don't probe the hash table in q-search either? I think I do, but don't have my source code handy to check. cheers, Peter
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