Author: Robert Hyatt
Date: 10:49:14 09/22/98
Go up one level in this thread
On September 21, 1998 at 19:45:21, José de Jesús García Ruvalcaba wrote: >On September 21, 1998 at 19:35:39, William H Rogers wrote: > >>On September 21, 1998 at 18:56:46, John Coffey wrote: >> >>>On September 21, 1998 at 18:12:36, Tom Kerrigan wrote: >>> >>>>Mostly correct, although maintaining two numbers to describe the position is >>>>overkill. One 64 bit number should be enough. >>>> >>> >>>Is one 64 bit number enough to uniquely identify a position? Does this >>>prevent two positions from getting the same hash key? >>> >>>I assume that you convert your hash key into an index into the history. >>>I assume that you take your 64 bit number and divide it by a constant >>>(or right shift it) to get the number of entries available in your hash >>>table? i.e. 64 megs would be 4 million positions. >>> >>>John Coffey >> >>That is why I suggested a smaller hash key of only 16 bits. That gives you 64K >>which is a lot for a smaller program. Think about it 64 thousand opening book >>replys. But the other boy are correct, if you have the space. > > What has to do the opening book with the hash tables? Are the opening book >positions stored in the hash tables somehow, at the beggining of the game? No... but using the hash key makes a convenient way of recognizing positions, by storing hash keys in the opening book file. Then, if you make a move, take the updated hash key and find it in the book file, you know that move is a book move...
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