Author: Amir Ban
Date: 06:55:59 10/18/98
Go up one level in this thread
On October 18, 1998 at 09:36:52, Robert Hyatt wrote:
>On October 18, 1998 at 07:41:29, Amir Ban wrote:
>
>>On October 18, 1998 at 05:46:50, Ed Schröder wrote:
>>
>>>Since ages I use the following formula for creating a set of random
>>>integers for hashing at program start:
>>>
>>>#define LENGTH 64*12
>>>
>>>int random [LENGTH];
>>>
>>>int a,b,c,d,x;
>>>
>>>srand(9); // initialize prime number
>>>
>>>for (x=0; x<LENGTGH; x++)
>>> { a=rand(); b=rand(); if (b & 1) a=a | 0x8000;
>>> c=rand(); d=rand(); if (d & 1) c=c | 0x8000;
>>> random[x]=(a<<16)+c;
>>> }
>>>
>>>I wonder how good such a system is and how others do it.
>>>
>>>- Ed -
>>
>>From the definition of LENGTH I guess these are piece-square tables you are
>>generating.
>>
>>I do the same, but I generate 48-bit numbers (actually only 45-bit, because I
>>don't bother completing the MSbit), not 32-bit as you do. I think it's generally
>>acknowledged that 32-bit is not enough ?
>>
>>Amir
>
>
>He is actually using more than 32 bits. We had a long discussion about
>this last year, where he is storing the move that produced this position
>(the move that takes him from the parent position to the current position
>in addition to the best move from this position). This is another way of
>adding bits (in his case I'd say the effect is like an extra 8-12 bits of
>hash signature...)
???
If you treat the move that produced the position as part of the key, then you
will not recognize transpositions.
Amir
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.