Author: Robert Hyatt
Date: 14:05:19 01/18/98
Go up one level in this thread
On January 18, 1998 at 16:41:30, Amir Ban wrote: > >I did some work on the ECM suite (please don't call it CCC, the original >text still deserves credit for it). I looked at the first 100. These >are somewhat easier than the rest. In under 20 seconds, I get 81 >correct. I am assuming (without good reason I admit) that since I solved >them these are correct, and I looked at the other 19. I ran them for >some more time, about a minute or so, and also visually analyzed them to >see if I can see what the problem is with them. Here is what I find. >Feel free to go over my analysis, and point out errors: what machine? I am getting 82 on a P6. Later I think you miss a key move in parsing the epd (note below) so you actually are getting 82 right according to the suite keys.. > >No. 11 (Nxg4): > >Junior immediately grabs Bb5 and sticks with it. I analyzed Nxg4 and >there is certainly some point to it. These are two completely different >plans, and although Bb5 seems better, I'm not sure. > >Recommend: Add Bb5 as a side solution. Crafty also found Bb5 as best. It locks on to this move at .7 seconds and never wavers, eval = +1.5... > > >No. 14 (Nd5): > >Junior finds Nb5 immediately. In the deeper analysis, it ultimately >prefers Nd5 slightly. Both moves have the same tactical idea. > >Recommend: No change (but would like to hear other opinions). > I get Nb5 at .71 seconds and it sticks. But it is all positional thru 9 plies. I only ran for 20 secs so I don't know if it would change later. eval =+.5 > >No. 17 (Rxd5): > >Junior finds Nf6+. After a long think, it prefers Rxd5 slightly. > >Recommend: No change, or add Nf6+ as side solution. Ditto. finds Nf6 at .1 seconds, eval slowly increases over next 20 seconds from 1.64 at ply=4 to 2.26 at ply=9... > > >No. 19 (Rxf6+): > >Rxf6+ simplifies nicely into a won endgame. However Junior never >considers it and find Nxe6 is really crushing. > >Recommend: Change key to Nxe6. Ditto. this must be a bug. However, Nf3 gets an eval of +4, Ne6 goes to +5. I don't like positions with 3 solutions... > > >No. 28 (Rxf4): > >A difficult problem, and somewhat vague. I am not close to finding it, >but by following the sequence Rxf4 Bxf4 Nxf6+ gxf6 Qg4+ Bg5 Bxg5 f5 it >looks like it does work in the sense that it's better than the >alternatives, but I cannot see a plus score. > >Recommend: No change, or else drop it for reason of vagueness. I get Bxf4 here, eval=-.9... > > >No. 29 (Rgxg6): > >A classical problem which is found easily. The idea is that after the >knight on g6 is gone, Qe5 wins. However, after a few seconds Junior >prefers an intermediate Rxa6 Qxa6 Rxg6 which is the same plan but more >effective. > >Recommend: Add Rxa6 as side solution. The problem is that playing Rxa6 >doesn't prove that your program understood this position. > > I get Rxa6 at shallow plies, +.3, but at depth=7, Rgxg6 fails high and resolves at +3... >No. 43 (Bxg2+): > >Junior takes Qxc2 fast and sticks with it, thinking that white is forced >to give up the exchange with Rxg4. Looks like this works, and is >somewhat better than the key. > >Recommend: Add Qxc2 as side solution. > Crafty gets Bxg2+ and sticks with it, eval=+1.51 at last iteration. What is your score for Qxc2?? > >No. 51 (Rxh2): > >Was not solved in 20 seconds, but turned out in the deeper think, but >with an unconvincing score. I didn't analyze it. > >Recommend: No change (but someone else should look at it). > > this one looks interesting. I get +2, Qc5... >No. 60 (Bxh2+): > >This one looks wrong. Junior has Qh6 which seems winning (Nf3 Nd2!). >Looks much more convincing than Bxh2+, where I don't see a win. > >Recommend: Change solution to Qh6. > > I agree. I get Bxh2 at very shallow searches, but Qh6 fails high at 2 seconds with score = +2 and this sticks for remainder of the search... Perhaps Bxh2 is as good later, no idea... >No. 63 (Ncxd5): > >Junior has Nbxd5, and this looks like a simple transpostion. > >Recommend: Add Nbxd5 as side solution. > > >No. 68 (Bd3): > >I don't understand the key move. Bd3 Qxc3 Rg4 Qxa1 Bxa1 Nxg4 Qxg4 g6 >looks like just a creative way to lose material. I don't see anything >else here. > >Recommend: Drop this problem. best crafty found was -2... looks lost rather than having a combination to win... > > >No. 71 (Qh6): > >Qh6 leads to material gain, and Junior finds it quickly, but after a few >seconds insists on the quiet and subtle Kg2! Black loses a rook at >least. > >Recommend: Change solution to Kg2. needs studying at deeper depths. I get Kg2 at shallow plies, but switch back to Qh6 at 7 and stick with it, eval=+3 thru 10 seconds when I stopped it. > > >No. 76 (fxg6): > >Junior switches to fxe6 and sticks with it. Analyzing both options, the >key is correct but fxe6 is at least as good. > >Recommend: Add fxe6 as side solution. > > I get +1.6 for fxe6, +3 for fxg6... >No. 78 (Nxc5): > >Was not found in 20 seconds, but turns up convincingly later. > >Recommend: No change. > > >No. 81 (Qb1+): > >Junior takes Bxc6, with idea Bxc6 Qd8 Qb1+. The idea of the key Qb1+ is >that the white queen is lost on a8 because of mate threats. Junior's >side solution uses the same idea, showing that the queen is equally lost >on d8 ! A nice cook. > >Recommend: Add Bxc6 as side solution. > > probably right. I get Bxc6 thru 9, at 10 Bxc6=+1.93, switches to Qb1+, eval=+2.03... not much difference at that depth... I get thru 11 in 20 seconds, no change... >No. 82 (exf6): > >Not found in 20 seconds, but turns up later. > >Recommend: No change. > > >No. 84 (Bg6): > >Junior plays the unspectacular cxb5. The key Bg6 looks sound, but it >only forces the exchange of heavy pieces and leads to an endgame with >advantage. > >Recommend: No change, or drop it on grounds of vagueness. > I get the same move... cxb5, eval =+1.2 > >No. 91 (Nc6): > >Junior switches between Nc6 and Nxe6. It finally adopts Nc6, but Nxe6 >may not be far behind. > >Recommend: No change. > > >No. 96 (Qe8+): > >This one's correct and is mate in 5, but so is Nf6+ with a different >move order. > >Recommend: Add Nf6+ as side solution. > my set has both Nf6 *and* Qe8 as solutions. I got this from ftp.onenet.net... Maybe you didn't pick up the second key move option from the epd suite... > >Amir
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