[Rexxx]

Originally posted by oleg:
I made a test in non-connected game. At the moment AI colonized all rock and gas planets in the system but before it discovered ice, it had two idle colonizers - one rock and one gas. I scraped them both - next turn, AI start to build one rock and one gas Rexx, I don't know why id did't work in your test. SE is a strange game should I say !

Did some tests (turn based, med/large quadrant, connected standard game, low bonus, AI as computer player)
I used
Entry 3 Type := Seeder (Gas)
Entry 3 Planet Per Item := 300
Entry 3 Must Have At Least := 5
Entry 4 Type := Seeder (Rock)
Entry 4 Planet Per Item := 300
Entry 4 Must Have At Least := 9
Entry 5 Type := Seeder (Ice)
Entry 5 Planet Per Item := 300
Entry 5 Must Have At Least := 12

In all tests my old statement "the AI only follows the Last (available) entry/name for a certain design type and the according must have number" was proven wrong!!!!

Until rock colonizing tech was discovered the AI build the 5 gas colonizers. After the first rock colonizers had been designed it immediately began to build them. NO DEAD END. At first it built 4 of them but when a slot got free the AI used it for a rock ship. After all gas colonizers were used up it constructed for lots of turns only 9 rock colonizers. However, at a certain point it switched back to gas colonizers. After checking the map I believe that this "switching back" happened when almost all the so far unused rock planets in the empire were colonized. It seems that the AI realized this fact and began to mix the colonizers to be used for further expansion. It never build the 5 gas ships I call for but mostly 1 or 2. However, once when two systems full of gas giants were discovered the AI did something quite intelligent: it began to build 8 gas colonizers!!!
Exactly the same happened when ice colonizing tech was discovered. For many many turns only ice colonizers were built to fill up the gaps of so far unused ice planets. Even when there was a large/huge rock planet with a breathable atmosphere available. Such a planet wasn't noticed until those "ice gaps" were filled up. When that was done the "switching back" to rock or gas colonizers happened again.
In all games the AI followed the "must have at least" number of the Last (available) entry but disregarded the other "number calls". Until ice colonizing tech was researched, there were always 9 colonizers available but never 5 gas and 4 rock. After ice colonizing tech was discovered there were 12 colonizers but never 5 gas, 4 rock, 3 ice.
The pattern the AI follows seems to be hardcoded, it overwrites my number calls:
When a new colonizing tech discovered the first thing to be done is filling up the gaps of uncolonized worlds (of this kind) in the empire while disregarding all other colonizable planets. After that fill up older gaps, then expand again and take into account which kinds of planets are available in adjacent systems. That – IMO – is exactly the AI's behaviour when I use a design-file which only calls for "colonizers" and not for names.

Oleg, you were completely right. Using the calling for names thing will avoid colonizer dead ends. Maybe I did something wrong in my tests using v 1.78, maybe something changed in v 1.84. Anyway, colonizer dead ends are avoidable.

After that I ran some tests using Master Belisarius' map and settings for his AI contest (simultaneous game). Again no dead ends but the colony bug he described is still happening.