What is tropism?

[tomgdrums]

Hi!

I just purchased Smarthink1.2o from Lokasoft and one of the adjustable settings is tropism. What does that mean and how does it affect aggressiveness and/or overall play of the engine?

Thanks!

[Kempelen]

Hi!

I just purchased Smarthink1.2o from Lokasoft and one of the adjustable settings is tropism. What does that mean and how does it affect aggressiveness and/or overall play of the engine?

Thanks!

From Chessprogramming wiki: http://chessprogramming.wikispaces.com/King+Safety

King tropism
King tropism is a simplified form of king safety evaluation. It takes into account the distance between the King and the attacking pieces, possibly weighted against piece value. For example, one may double the distance value for a queen, and halve it for bishops and rooks. This kind of evaluation acts in a probabilistic way - it is by no means certain that being close to the king helps in attacking it. For example, if white castles short, black rook on h8 gets a higher tropism value regardless whether it stands on an open file. Nevertheless, using this kind of crude evaluation term increases a probability of building up an attack. This kind of algorithm is used by Crafty. Another, perhaps more basic example is the CPW-engine.

Basically: is how pieze distances to king affect to king safety

[Matthias Gemuh]

Hi!

I just purchased Smarthink1.2o from Lokasoft and one of the adjustable settings is tropism. What does that mean and how does it affect aggressiveness and/or overall play of the engine?

Thanks!

Higher tropism means more attackers are encouraged to move closer to attacked piece (usually the opponent's king).
Too high tropism can hurt as attackers neglect other duties.

Matthias.