Author: Robert Hyatt
Date: 17:15:16 08/29/04
Go up one level in this thread
On August 29, 2004 at 01:16:31, Stuart Cracraft wrote: >On August 27, 2004 at 23:34:47, Robert Hyatt wrote: > >>On August 27, 2004 at 22:47:56, Stuart Cracraft wrote: >> >>>On August 26, 2004 at 11:39:31, Robert Hyatt wrote: >>> >>>>On August 25, 2004 at 12:52:46, Volker Böhm wrote: >>>> >>>>> >>>>>Hi, >>>>> >>>>>the following position of the iq - test (position 166) cannot be solved from >>>>>spike in reasonalbe time (> 2h): >>>>> >>>>>r4r1k/6pp/3p3b/1p1Npb2/3nB2q/2N3P1/PP3P1P/R2Q1RK1 b - - 0 1 >>>>> >>>>>(The move to find is Qxe4) >>>>> >>>>>The reason is a nullmove-problem. After the queen-sac there are many moves that >>>>>leads to a mate-thread. But one queen back spike tends to prune because of >>>>>nullmove result. >>>>> >>>>>I tested the position with fritz 8, he solves it in 8 ply in nearly no time. >>>>>(PRODEO NEEDS 7 Ply, Ruffian 1.01 11 Ply). >>>>> >>>>>Are there non commercial engines that solves this position too in a short amount >>>>>of time? >>>>>Maybe the author of this engine would be so kind to explain the rule that solves >>>>>the nullmove-problem. >>>>> >>>>>Thanks Volker >>>> >>>> >>>>Here is my output: >>>> >>>> 8-> 0.23 -0.16 1. ... Qh3 2. Bg2 Qg4 3. Ne3 Qxd1 4. >>>> Rfxd1 Rac8 5. Nxf5 Rxf5 6. Nd5 (s=2) >>>> 9 0.47 -0.03 1. ... Qh3 2. Bxf5 Qxf5 3. f4 Rab8 >>>> 4. fxe5 Qxe5 5. Qd3 Rxf1+ 6. Qxf1 Be3+ >>>> 7. Nxe3 Qxe3+ 8. Qf2 >>>> 9 0.68 -1 1. ... Qxe4!! >>>> 9 0.71 -1.01 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. a4 bxc3 6. bxc3 >>>> 9-> 0.71 -1.01 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. a4 bxc3 6. bxc3 (s=6) >>>> 10 0.75 -1.01 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. a4 bxc3 6. bxc3 (s=5) >>>> 10-> 0.85 -1.01 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. a4 bxc3 6. bxc3 (s=3) >>>> 11 0.97 -1.28 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfe1 bxc3 6. bxc3 Ra3 >>>> (s=2) >>>> 11-> 1.19 -1.28 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfe1 bxc3 6. bxc3 Ra3 >>>> (s=3) >>>> 12 1.36 -1.22 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfe1 bxc3 6. bxc3 Ra3 >>>> 7. Rab1 (s=2) >>>> 12-> 2.57 -1.22 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfe1 bxc3 6. bxc3 Ra3 >>>> 7. Rab1 (s=3) >>>> 13 3.00 -1.25 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfe1 bxc3 6. bxc3 Ra3 >>>> 7. Qc4 Nc2 (s=2) >>>> 13-> 4.70 -1.25 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfe1 bxc3 6. bxc3 Ra3 >>>> 7. Qc4 Nc2 (s=3) >>>> 14 6.08 -1.47 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfb1 bxc3 6. bxc3 Ne2+ >>>> 7. Kf1 Rad8 8. Rb6 e4 (s=2) >>>> 14-> 18.31 -1.47 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rfb1 bxc3 6. bxc3 Ne2+ >>>> 7. Kf1 Rad8 8. Rb6 e4 (s=3) >>>> 15 22.98 -1.67 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rae1 bxc3 6. bxc3 Ra3 >>>> 7. Qc4 Nc2 8. Rb1 Bd2 (s=2) >>>> 15-> 32.85 -1.67 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rae1 bxc3 6. bxc3 Ra3 >>>> 7. Qc4 Nc2 8. Rb1 Bd2 (s=3) >>>> 16 38.96 -1.54 1. ... Qxe4 2. Nxe4 Bxe4 3. Nc3 Bf3 >>>> 4. Qd3 b4 5. Rae1 bxc3 6. bxc3 Ra3 >>>> 7. Qc4 Nc2 8. Rb1 Bd2 9. Qe6 (s=2) >>> >>>In your output, what does s=2 and s=3 mean? >> >>Means there are 2 or 3 moves that are apparently capable of becoming the best >>move on the next iteration. The parallel search searches them one at a time, >>using all processors, before splitting the rest of the root moves and searching >>each with one processor for better search efficiency. >> >>>How about !! ? And is the -value relative to the >>>side on move? >> >>!! means beta cutoff (fail high at the root) on this move. >> >> >> >>> Finally, is this your 4-cpu Xeon? >> >>No, quad 2.4ghz opteron that I used in the WCCC this year. >> > >Forget the prior question on the previous post -- got the answer >here. > >> >> >>>If so, what speed are the chips and what are >>>the characteristics that distinguish between >>>the Xeon and a regular Intel chip? >>> >>>Stuart > >Can you characterize what you hypothesize are the things that >the top programs have that Crafty might not yet have that explain >any gap in performance, however slight? What is the gap between >Crafty and Junior or Shredder or any of the other perennial >winners of the various events? > >Stuart Several things. Most have a better search with forward pruning, where I am not forward pruning at all other than with the normal null-move stuff. Most have a much better tuned evaluation although I'll take my chances with them in endgames. Probably the main thing is their opening book preparation however...
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