Major fixes to the xconq AI code

[Hans Ronne <hronne at pp dot sbbs dot se>]

I have just checked in several major fixes and improvements to the AI code.
The result is a much more aggressive AI that no longer sends lots of units
into reserve mode each turn. Reallocation of troops from one front to
another by the AI also works better now. Some of the changes are:

1. A particularly nasty bug that caused lots of units to go into reserve
mode each turn has been fixed. the problem was in the precomputed unit
worth code, where dice values (used to compute random damage) were not
handled correctly. As a consequence the AI would think that some unit types
were worthless and therefore send them into reserve. Affected games: every
one that uses dices, i.e.

africa.g, ancient.g, beirut.g, cave.g, cave2.g, empire.g, flattop.g,
fred.g, gettysburg.g, greek.g, insects.g, mormon.g, panzer.g, pgu.g,
tailhook.g, tank.g, ww2-adv.g, ww2-bn.g, ww2-div-eur.g

and all modules derived from them.

2. A bug that caused units that could not be repaired to go into repair
mode and get stuck there forever has been fixed.

3. The way that the AI handles cases where units cannot do something
sensible (because there are no enemies left nearby) has been improved.
Previously, such units would just be sent into reserve mode, and the
problem would reappear every turn. Now, they are forced to replan, so that
they can get reassigned to another front. This is important for the AI's
ability to use all its available forces in the best way.

4. A bug that caused replanning each turn for exploratory units has been fixed.

5. The way that the AI assigns new unit plans has been improved.

6. The problem with colonizers that try to build cities in forbidden
locations (noted by Lincoln Peters) has been fixed. The fix also handles
several other possible problems that could prevent a city from being built.

To see the difference after the fixes, run flattop.g on automatic. The two
AI sides now fight this game very aggressively, and always to the bitter
end. Units are no longer goofing around.

Hans

Hans Ronne

hronne@pp.sbbs.se