The prisoner's dilemma tournament is over. There were a total of 21 entries. The winner is Margaret Sy, with a total of 39 points. 2nd and 3rd place go to rpglover64 and THE BLACK KNIGHT, with scores of 38 and 36 points respectively. There were some fairly intricate strategies in the tournament, but all three of these top scorers submitted programs that completely ignored the source code of the other player and acted randomly, with the winner having a bias towards defecting.

You can download a chart describing the outcomes here, and the source codes for the entries can be downloaded here.

I represented each submission with a single letter while running the tournament. Here is a directory of the entries, along with their scores: (some people gave me a term to refer to the player by, while others gave me a term to refer to the program. I went with whatever they gave me, and if they gave me both, I put the player first and then the program)

A: rpglover64 (38)

B: Watson Ladd (27)

c: THE BLACK KNIGHT (36)

D: skepsci (24)

E: Devin Bayer (30)

F: Billy, Mimic-- (27)

G: itaibn (34)

H: CooperateBot (24)

I: Sean Nolan (28)

J: oaz (26)

K: selbram (34)

L: Alexei (25)

M: LEmma (25)

N: BloodyShrimp (34)

O: caa (32)

P: nshepperd (25)

Q: Margaret Sy (39)

R: So8res, NateBot (33)

S: Quinn (33)

T: HonoreDB (23)

U: SlappedTogetherAtTheLastMinuteBot (20)

Sorry if this is a stupid question, but this tournament looked to me like a thinly disguised version of:

"Construct a robot that can read code and interpret what it means."

which is a Really Hard Problem.

Is that not a fair description? Was there some other way to approach the problem?

The only way I can see to go about constructing a GOOD entrant to this is to write something that can take as its input the code of the opponent and interpret what it will actually DO, that can recognize the equivalence between (say):

return DEFECT

and

if 1: return ... (read more)

Perfect simulation is not only really hard, it has been proven to be impossible. See http://en.wikipedia.org/wiki/Halting_problem