Author: Graham Banks
Date: 20:41:23 01/14/05
As CM9000 Minotaur 2 is my final attempt at CM9000 supremacy before concentrating more on CM10th, here are my observations based on watching and playing through many games at longer time controls involving different CM9000 settings. POSITIONAL VALUES Control of the centre is often vital to gaining control of the game in my opinion. A value of 100 to 110 seems right for both own and opponent. Mobility is important as when two engines battle it out, a passive position can often lead to defeat. On the other hand, playing too loosely can leave one’s position vulnerable. A value of 110 seems to strike a good balance for both own and opponent. King safety. Against stronger engines, CM9000 settings can get crunched by kingside attacks unless its own king safety value is 160 or more. Even 165 was insufficient for Minotaur against such monsters as Fritz 8 Bilbao and Deep Junior 9 which is why Minotaur 2 has 180. If you have high king safety values for both own and opponent, I feel that CM9000 will neglect other areas of its game and against strong allround engines, their defense is good and they will often overwhelm CM9000 elsewhere on the board. This is why Judge II (king safety settings of 175 for both own and opponent) does not fare well in top company. It is also why Minotaur 2 has 180 for own and the default 100 for opponent. Passed Pawns. CM9000 often seems susceptible to defeat through underestimating an opposing passed pawn. This is why I think opponents passes pawn value should be set at between 110 and 125. Raising own passed pawn value too much often sees CM9000 conceding weaknesses in other areas to create a passed pawn which it doesn’t always handle well anyway. Keeping both own and opponents value the same seems okay at about 110, but I wouldn’t raise own value higher. Pawn Weakness. This area has a crucial effect on the playing syle of the personality! If you have both own and opponents value too high (example 120 or higher), you will tend to get closed games which do not suit computers due to a preference to maintain pawn chains. Own value too high and opponents much lower (example own 120 opponents 105 as in Minotaur) will see the personality sometimes give up a pawn, often without sufficient compensation, thus leading to eventual loss if the opponent survives any pressure and turns it around. I’ve come to the conclusion that keeping both own and opponents vaue the same is best – probably in the range of 105 to 115. MATERIAL VALUES Tricky, but these are my thoughts: In most situations a minor piece is better than three pawns, therefore P=1.0 and N=3.1 is preferable. I have finally come to the unshakeable conclusion that in computer chess, a bishop is stronger than a knight, especially as you don’t get too any closed games. This is why settings that have A/D settings of -2 with a higher bishop than knight value (as in Slayer) can be advantageous. Encouraging exchanges and preferring bishops often leads to winning endgames. Therefore B=3.2 would seem right. A rook is slightly stronger than minor piece and two pawns in most situations (especially knight and two pawns), so R=5.2 or 5.3 would seem about right. Computers use the queen very effectively and definitely the value should be higher than three minor pieces or a rook, minor piece and pawn. A queen and pawn more often than not defeats two rooks in computer play, so the queen value should also take this into account. Therefore Q=9.6 or higher. I’ve seen some settings where the own queen has a higher value than the opponents queen. Of course, the idea is to discourage the exchange of queens, especially when things aren’t going so well. I am now against this idea as I’ve seen such avoidance lead to a deterioration of position and eventually loss of the game on several occasions. SELECTIVITY For CM9000 selectivity 12 seems strongest with most top settings using this. The main exception is probably Judge which does well with selectivity 11. A/D (Attack/Defense) I prefer to keep this at 0, but as mentioned previously -2 could be best. Of course a positive value prefers to avoid exchanges whereas a negative value prefers them (as explained in the manual). Nothing to do with a preference for attack over defense as such, so rather misleading! M/P (Material/Position) Be aware that altering this setting from the default 0 will have a major impact on material and positional values also. Best example of this is the R1 setting. Using the Crafty output file (Wilhelm correct me if I’m wrong!) will show this. This is why the CM GUI settings and Chessbase settings for R1 are different. Be careful! I prefer to keep the setting at 0, but a slight negative value definitely seems to be more beneficial than a positive value.
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