Author: Stuart Cracraft
Date: 14:22:04 08/11/04
Go up one level in this thread
On August 10, 2004 at 13:07:21, Robert Hyatt wrote: >On August 09, 2004 at 14:26:18, Stuart Cracraft wrote: > >>Sorry, the posted position was in error. It is: >> >>>[D]r1bqkb1r/2pp1ppp/p1n2n2/1p2p3/4P3/1B3N2/PPPP1PPP/RNBQ1RK1 b q - 4 1 >> >>On August 09, 2004 at 14:25:30, Stuart Cracraft wrote: >> >>>[D]r1bqkb1r/2pp1ppp/p1n2p2/1p2p3/4P3/1B3N2/PPPP1PPP/RNBQ1RK1 b q - 4 1 >>> >>>I don't know if I filled in the castle flags right but in this position >>>black still has both rights left. >>> >>>The question is, if your program values bishops more than knights, >>>how do you prevent it from playing Na5 to capture the White Bishop >>>but then giving up the pawn at e5 (since the capture Nxe4 by black >>>is unplayable). (e.g. 1. ... Na5 2. Nxe5 Nxb3 3. ab) >>> >>>I've searched this to 10 full ply with unlimited quiescence >>>and it still can't see that Na5 is bad. >>> >>>It would help if some people posted their searches and mention >>>how they avoid this kind of issue. >>> >>>My search: >>> >>>Alpha=-255 Beta=245 Maxdepth=99 MaxTime=9999999 >>> 1/11> c6a5 0.00 245 68 c6a5 >>> 1/11 f6e4 0.01 1026 159 f6e4 >>> 2/15 f6e4 0.01 1008 946 f6e4 f1e1 >>> 3/17< f6e4 0.02 758 4181 f6e4 d2d4 e5d4 >>> 3/20 f6e4 0.04 75 7143 f6e4 b3d5 e4f6 >>> 4/30 f6e4 0.13 75 24970 f6e4 b3d5 e4f6 d5c6 >>> 5/34 c6a5 0.50 57 104715 c6a5 f1e1 a5b3 a2b3 c8b7 >>> 6/34 c6a5 1.22 45 256985 c6a5 f1e1 a5b3 a2b3 c8b7 b1c3 >>> 7/42 c6a5 4.31 32 889215 c6a5 f3e5 a5b3 c2b3 f8d6 d2d4 f6e4 >>> 8/51 c6a5 24.86 19 5021946 c6a5 f3e5 a5b3 c2b3 d8e7 d2d4 d7d6 e5f3 >>> 9/54 c6a5 115.27 19 19483875 c6a5 f3e5 a5b3 c2b3 d8e7 d2d4 d7d6 e5f3 >>>10/54 c6a5 264.28 26 44999682 c6a5 f1e1 a5b3 a2b3 c8b7 d2d4 f6e4 b1d2 d7d5 >> >>> >>>Stuart > > >The output above looks broken. Why not just take the pawn. Here is Crafty >after I play Na5 as black: > > 1 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4 > 1-> 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4 > 2 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4 > 2-> 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4 > 3 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4 > 3-> 0.09 0.47 2. Nxe5 Nxb3 3. axb3 Nxe4 > 4 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5 > 5. dxe5 Nxe4 > 4-> 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5 > 5. dxe5 Nxe4 > 5 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5 > 5. dxe5 Nxe4 > 5-> 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5 > 5. dxe5 Nxe4 (s=2) > 6 0.10 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5 > 5. dxe5 Nxe4 > 6-> 0.11 0.61 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bxe5 > 5. dxe5 Nxe4 (s=2) > 7 0.11 0.80 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bb7 > 5. f3 O-O > 7-> 0.12 0.80 2. Nxe5 Nxb3 3. axb3 Bd6 4. d4 Bb7 > 5. f3 O-O (s=2) > 8 0.15 0.85 2. Nxe5 Nxb3 3. axb3 d6 4. Nf3 Be6 > 5. e5 Ne4 6. d4 > 8-> 0.17 0.85 2. Nxe5 Nxb3 3. axb3 d6 4. Nf3 Be6 > 5. e5 Ne4 6. d4 > 9 0.22 0.65 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Nxe4 6. d3 c5 > 9-> 0.35 0.65 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Nxe4 6. d3 c5 (s=3) > 10 0.44 0.97 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Be7 6. d4 O-O 7. Nc3 (s=2) > 10-> 0.54 0.97 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Be7 6. d4 O-O 7. Nc3 (s=2) > 11 0.70 0.78 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Be7 6. d4 O-O 7. Nc3 Bb7 > 11-> 2.44 0.78 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Be7 6. d4 O-O 7. Nc3 Bb7 (s=4) > 12 3.03 0.83 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nd4 Be7 6. Qf3 O-O 7. Nc3 b4 8. > e5 (s=3) > 12-> 6.44 0.83 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nd4 Be7 6. Qf3 O-O 7. Nc3 b4 8. > e5 (s=5) > 13 10.00 0.88 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Be7 6. Nc3 O-O 7. Qf3 Bb7 8. > d4 Qg4 <HT> (s=4) > 13-> 18.39 0.88 2. Nxe5 Nxb3 3. axb3 d6 4. Nc6 Qd7 > 5. Nb4 Be7 6. Nc3 O-O 7. Qf3 Bb7 8. > d4 Qg4 <HT> (s=4) > 14 31.39 0.82 2. Nxe5 Nxb3 3. axb3 Bb7 4. d4 Be7 > 5. f3 d6 6. Nd3 O-O 7. c4 c5 8. cxb5 > axb5 9. Rxa8 Bxa8 (s=3) > 14-> 55.88 0.82 2. Nxe5 Nxb3 3. axb3 Bb7 4. d4 Be7 > 5. f3 d6 6. Nd3 O-O 7. c4 c5 8. cxb5 > axb5 9. Rxa8 Bxa8 (s=3) > 15 1:28 0.80 2. Nxe5 Nxb3 3. axb3 Be7 4. d4 O-O > 5. f3 d6 6. Nc6 Qd7 7. Nxe7+ Qxe7 8. > Bg5 h6 9. Bxf6 Qxf6 10. Nc3 Re8 (s=2) > 15-> 3:00 0.80 2. Nxe5 Nxb3 3. axb3 Be7 4. d4 O-O > 5. f3 d6 6. Nc6 Qd7 7. Nxe7+ Qxe7 8. > Bg5 h6 9. Bxf6 Qxf6 10. Nc3 Re8 (s=4) Black cannot play Na5 because of Nxe5 and the loss of a pawn. So my question was / still is, what should Black instead of Na5 if the program values Knights more than Bishops? Mine plays Na5, gets the Bishop for the Knight and then promptly loses a center pawn. I could decrease the value of the Bishop or increase the value of the center pawn, but both of these seem a little extreme given Bishop vs. Knight and the current high value of a center pawn. The point is that a center pawn in this program is not worth as much as a Bishop minus a Knight. The former is maybe 30 or 40 millipawns and the latter is maybe 100 or 200 millipawns. I am looking for good ways to avoid 1. ... Na5 in the first place. A knight on the rim penalty doesn't do it since the Knight is just traded off. Valuing the center pawn too much makes no sense. I am running out of ideas to prevent 1. ... Na5. Stuart
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