Investigation of AI personalities

[therother]

At the request of tai4ji2x, this thread is for investigating AI personalities.

These are the offical descriptions of the various options in descr_strat.txt:

These control a set of AI production personalities, which contribute a bias towards building and training (but not retraining or repairing). This bias is fairly small compared to game-generated factors such as "the enemy is attacking me with lots of cavalry, build me some spearmen". Explaining the weighting system which drives the production AI in full is beyond the scope of this document as it would take several days to write.

So in short, the building construction personalities are these: (ranked highest to lowest - therother)

balanced - biases towards growth, taxable income, trade level bonuses (roads), walls and xp bonus buildings

religious - biases towards growth, loyalty, taxable income, farming, walls and law

trader - biases towards growth, trade level, trade base, weapon upgrades, games, races and xp bonus buildings

comfort - biases towards growth, farming, games, races, xp bonus and happiness

bureaucrat - biases towards taxable income, growth, pop health, trade, walls, improved bodyguards and law

craftsman - biases towards walls, races, taxable income, weapon upgrades, xp bonuses, mines, health and growth

sailor - biases towards sea trade, taxable income, walls, growth, trade

fortified - biases towards walls, taxable income, growth, loyalty, defenses, bodyguards and law

These biases are towards building properties, rather than buildings themselves. The game does not know what a "Blacksmith" is, for example, it only knows that it is a building which provides a weapon upgrade, and hence a Craftsman AI would be more likely to build it than another AI personality type.

These are then combined with a troop production personality, as follows:

smith - exactly level

mao - biased towards mass troops, light infantry

genghis - biased towards missile cavalry and light cavalry

stalin - biased towards heavy infantry, mass troops and artillery

napoleon - biased towards a mix of light and heavy infantry, light cavalry

henry - biased towards heavy and light cavalry, missile infantry

Caesar - biased towards heavy infantry, light cavalry, siege artillery

The same system as for the buildings applies. Troop category and class are combined at the time the unit database is loaded to give a unit production type, and the likelihood of the AI choosing to produce a given unit type which can be produced is then modified by the unit type weighting. There is also a random element in the choosing of which building or troop type to produce next, so the effect of the bias is a statistical thing. Another factor that is applied over the top which may obscure the bias is a tendency towards producing troop mixtures (according to what is already in the garrison) and a weighting according to unit strength.

The two sets of types can be freely combined; for example, although Fortified Caesar does not appear in the list of options currently used by the vanilla RTW game, it is a valid combination.