Author: Uri Blass
Date: 18:23:13 03/02/06
Go up one level in this thread
On March 02, 2006 at 14:52:47, Robert Hyatt wrote: >On March 02, 2006 at 14:14:15, Paul Clarke wrote: > >>On March 02, 2006 at 11:50:56, Robert Hyatt wrote: >> >>>On March 02, 2006 at 02:19:04, Tony Werten wrote: >>> >>>>On March 01, 2006 at 20:00:40, Robert Hyatt wrote: >>>> >>>>>Someone had already emailed me this. I just hadn't looked. Now I am not quite >>>>>sure what is going on: >>>>> >>>>>static const int HistorySize = 12 * 64; >>>>> >>>>>That appears to be a dimension for the HistHit[] and HistTot[] arrays, which >>>>>leaves me lost since the other code sent to me has: >>>>> >>>>>index = PIECE_TO_12(board->square[MOVE_FROM(move)]) * 64 + >>>>>SQUARE_TO_64(MOVE_TO(move)); >>>>> >>>>>followed by >>>>> >>>>> HistHit[index]++; >>>>> HistTot[index]++; >>>>> >>>>>So I know I am overlooking something. "index" is clearly a 12 bit value between >>>>>0 and 4095 if I understand it correctly. yet HistHit[] is not nearly that big. >>>> >>>>How do you get to 4096 ? >>> >>>I'm looking at from*64+to... since either is at least 6 bits, that gives 12. >>>If piece_to_12 squashes from into 12 bits, that would at least make the index >>>correct according to the dimension of the array, although then I would not claim >>>to understand the idea of squashing from from 0-63 into the range 0-11... >> >>Are you reading the index calculation as: >> >>index = SQUARE_TO_64(MOVE(from)) * 64 + SQUARE_TO_64(MOVE(to)); >> >>? If so then that would explain the confusion: the index calculation is, as Tony >>mentions below, using the type of piece that moved rather than the square it >>moved from, hence the use of PIECE_TO_12(board->square[MOVE(from)]). > >Aha... So fruit is using a 12 * 64 entry hit/fh counter set. Has anyone >compared this to the more common 64-64 (from-to 12 bits) array??? > >The snippet that was emailed to me didn't have the PIECE_TO_12() macro/function >included so I didn't notice, I was assuming it was a 12 bit thing rather than a >12-valued thing... :) You can easily get the full source of fruit in http://arctrix.com/nas/fruit/ Uri
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.