My chess engine ISA is current in developpement
It has only alpha beta + PVS + quiesce , hashtables and eval with materiel , pst , passed , doubled ,isolated pawns , square rule , and rule for winning KBB vs K and KBN vs K.
I use this kind of position to see if hashtables work :
FEN "4k3/8/4pPp1/3pP1P1/2pP4/2P3K1/8/8 w - - 0 1"
Here is the list of moves by ISA :
Code: Select all
1. Kf4 {(g3f4) +7.65/28 12} Kf7 2. Ke3 {(f4e3) +7.95/27 10} Ke8
3. Kf4{(e3f4) +10.84/27 10} Kf7 4. Ke3 {(f4e3) +7.65/24 10} Ke8 5. Kd2 {(e3d2)+7.95/24 10} Kf7
6. Kc2 {(d2c2) +12.76/27 10} Kf8 7. Kd2 {(c2d2) +17.78/2710} Kf7 8. Kc1 {(d2c1) +8.96/24 10} Ke8
9. Kb2 {(c1b2) +17.78/24 10} Kd710. Kc2 {(b2c2) +7.95/19 10} Ke8 11. Kb1 {(c2b1) +12.76/25 10} Kd7
12. Kb2{(b1b2) +7.50/18 10} Ke8 13. Ka3 {(b2a3) +17.78/23 10} Kd7 14. Kb4 {(a3b4)+8.96/18 10} Ke8
15. Kc5 {(b4c5) +M9/20 1} Kd7 16. Kb5 {(c5b5) +10.84/1910} Ke8 17. Kc6 {(b5c6) +M9/20 2} Kd8
18. Kd6 {(c6d6) +M7/16 1} Ke8 19.Kxe6 {(d6e6) +M6/14 0} Kf8 20. f7 {(f6f7) +M5/12 0} Kg7
21. Ke7 (e6e7)+M4/10 0} Kh8 {(g7h8) -M4/9 0} 22. Kf6 {(e7f6) +M3/8 0} Kh7 23. e6 {(e5e6)+M2/6 0} Kh8
24. f8=Q+ {(f7f8) +M1/4 0} Kh7 25. Qg7# {(f8g7) +M0/2 0} 1-0
It find the winning way but I've noticed two stranges king take back :
7. Kd2 {(c2d2) +17.78/2710}
and
10. Kc2 {(b2c2) +7.95/19 10}
Do you think it's a bug in search?hashtables?eval?
Bests
Dany