Author: Anthony Cozzie
Date: 04:55:21 11/20/03
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On November 19, 2003 at 14:27:59, Tord Romstad wrote: >On November 19, 2003 at 12:16:52, Anthony Cozzie wrote: > >>Zappa uses tables; they are 32KB in size. What on earth are you doing that >>makes it several hundred KB? > >A slightly simplified description of what I do: > >My SEE lookup table is indexed by the piece under attack (in the range 0..5) >and the entries of the attack tables for both sides (in the range 0..255). >Hence the total size of the array is 6*256*256=327680 bytes. > >From the description on Ed's pages, it looks like he is doing almost exactly >the same. > >How does your 32KB table look, and how do you use it? > >Tord I get rid of the 0-5 index. It only costs a few ops to put it back. My code looks like this: static zforceinline int see_capture(zpos *p, zmove m) { int mg, dmg; mg = mat_gain(p, m); dmg = abs_piece_value[m_ptype(m)]; return int_min(mg, mg - (dmg + see_noncapture(p, m))); } see_noncapture says, if I move my piece to this square, what happens. In range 0 - -Q. So the defense has two choices: Recapture (second choice) or leave it alone (first choice). The mat_gain function is basically "value of piece on square" except that it also handles promotions. Right now I am compressing the table to 4 bit quantities, but I'm about to get rid of that . . anthony
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