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H.G.Muller

Joined: 10 Mar 2006
Posts: 21989
Location: Amsterdam

Post subject: Re: How to implement KPK ?    Posted: Thu Mar 21, 2013 11:52 am

Ah, you make use of left-right symmetry. Nice idea. I now did that too, by adding a >>1 to the Pawn square during packing, and incrementing it in steps of 2. This should throw away all positions where the Pawn is on an odd file. (A bit wasteful, as the generation still uses the full set of positions, but the assumption was this would be infinitely fast anyway, or that speed would not be important because you save it on a file.)

The following code is tested in the sense that it compiles (there was a missing semicolon), and runs without segfaulting (I had forgotten to convert the 0x88 to-square back to a normal square index.)

 Code: /* Public-domain KPK bitbase code by H.G. Muller */ #define WTM 0 #define BTM 1 char dtc[2][64][64][64]; // 512 KB char bitbase[2*64*64*3]; char steps[] = {1, -1, 16, -16, 15, -15, 17, -17}; void Init () {   int wk, bk, p;   for(wk=0; wk<64; wk++) for(bk=0; bk<64; bk++) for(p=0; p<64; p++) {     if(bk == wk) dtc[BTM][wk][p][bk] = 1, dtc[WTM][wk][p][bk] = -1; else     if(wk == p) dtc[BTM][wk][p][bk] = dtc[WTM][wk][p][bk] = -1; else     if(bk ==  p) dtc[BTM][wk][p][bk] = -1; else // with WTM black just captured P     if(p >= 56) dtc[WTM][wk][p][bk] = 1; // promoted and on move = win   } } void Pass (int stm) {   int wk, bk, p, d;   for(wk=0; wk<64; wk++) for(bk=0; bk<64; bk++) for(p=0; p<64; p++) {     int k = stm == WTM ? wk : bk;     int O88 = (k & 070) + k; // 0x88 square number of King     if(dtc[stm][wk][p][bk]) continue; // already decided     dtc[stm][wk][p][bk] = stm;  // assume lost if btm, undecided if wtm     if(bk != p && stm == WTM) { // pawn not captured, so can move       if(p+8 != bk && dtc[BTM][wk][p+8][bk] > 0)  { dtc[WTM][wk][p][bk] = 1; continue; }       if(p+7 == bk && (p & 7) != 0)  { dtc[WTM][wk][p][bk] = 1; continue; }       if(p+9 == bk && (p & 7) != 7)  { dtc[WTM][wk][p][bk] = 1; continue; }     }     for(d=0; d<8; d++) {       int to = O88 + steps[d];       if(to & 0x88) continue; // off board       to -= to>>1 & 070;       if(stm == WTM ? dtc[BTM][to][p][bk] > 0 : dtc[WTM][wk][p][to] > 0)       { dtc[stm][wk][p][bk] = !stm; break; }     }   } } void Pack () {   int wk, bk, p, i;   for(wk=0; wk<64; wk++) for(bk=0; bk<64; bk++) for(p=8; p<56; p+=2) {     int index = (bk >> 3) + 8*wk + 8*64*(p-8>>1);     bitbase[2*index] |= (dtc[WTM][wk][p][bk] > 0) << (bk & 7);     bitbase[2*index+1] |= (dtc[BTM][wk][p][bk] > 0) << (bk & 7);   } } void Build () {   int i;   Init();   for(i=0; i<100; i++) // won't take more than 100 moves     Pass(WTM), Pass(BTM);   Pack(); }

When I run it, it prints

 Code: white to move: 211980+, 23085=, 27079- black to move: 140386+, 113694=, 8064-

where = and - together count the non-won positions (which are not properly distinguished by the algorithm), and + the number of listed wins.

 O, I guess it still needs a stalemate correction.
 Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First
Subject Author Date/Time
Chan Rasjid Thu Mar 21, 2013 3:43 am
H.G.Muller Thu Mar 21, 2013 7:46 am
Chan Rasjid Thu Mar 21, 2013 8:27 am
H.G.Muller Thu Mar 21, 2013 10:07 am
H.G.Muller Thu Mar 21, 2013 10:33 am
Chan Rasjid Thu Mar 21, 2013 6:10 pm
Don Dailey Tue Apr 02, 2013 6:56 pm
Lucas Braesch Thu Mar 21, 2013 11:03 am
Re: How to implement KPK ? H.G.Muller Thu Mar 21, 2013 11:52 am
Lucas Braesch Thu Mar 21, 2013 12:04 pm
H.G.Muller Thu Mar 21, 2013 6:36 pm
H.G.Muller Thu Mar 21, 2013 9:00 pm
Chan Rasjid Sat Mar 30, 2013 8:15 am
Evert Glebbeek Sat Mar 30, 2013 8:42 am
Sven Schüle Sat Mar 30, 2013 12:12 pm
Chan Rasjid Sat Mar 30, 2013 12:20 pm
Sven Schüle Sat Mar 30, 2013 12:42 pm
Chan Rasjid Sat Mar 30, 2013 2:03 pm
Sven Schüle Sat Mar 30, 2013 6:29 pm
Wylie Garvin Sat Mar 30, 2013 12:50 pm
Chan Rasjid Sat Mar 30, 2013 1:53 pm
Evert Glebbeek Sat Mar 30, 2013 2:03 pm
H.G.Muller Sat Mar 30, 2013 2:26 pm
Sven Schüle Sat Mar 30, 2013 6:38 pm
H.G.Muller Sat Mar 30, 2013 8:13 pm
Sven Schüle Sat Mar 30, 2013 8:58 pm
H.G.Muller Sat Mar 30, 2013 10:58 pm
Sven Schüle Sat Mar 30, 2013 11:51 pm
H.G.Muller Sun Mar 31, 2013 7:35 am
Sven Schüle Sun Mar 31, 2013 9:02 am
H.G.Muller Sun Mar 31, 2013 9:09 am
Sven Schüle Sun Mar 31, 2013 9:13 am
Steven Edwards Mon May 13, 2013 2:14 am
Don Dailey Mon May 13, 2013 2:20 am
Chan Rasjid Sat Mar 30, 2013 12:18 pm
H.G.Muller Sat Mar 30, 2013 9:08 am
Chan Rasjid Sun May 12, 2013 10:27 pm
Ronald de Man Sun May 12, 2013 11:11 pm
Chan Rasjid Mon May 13, 2013 7:39 am
Don Dailey Mon May 13, 2013 2:14 am
Steven Edwards Tue May 14, 2013 7:19 am
Chan Rasjid Tue May 14, 2013 2:45 pm
Chan Rasjid Tue May 14, 2013 2:50 pm

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