Author: Robert Hyatt
Date: 20:34:47 08/27/04
Go up one level in this thread
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. >If so, what speed are the chips and what are >the characteristics that distinguish between >the Xeon and a regular Intel chip? > >Stuart
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