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Subject: Re: What makes Junior so good?

Author: Robert Hyatt

Date: 15:50:24 05/01/00

Go up one level in this thread


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.

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...



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