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David Liepmann Professor Cass, Advising. Experimental Iterated Competition with Artificially Intelligent Go Agents. The Game and GNU Go. 19x19 board Two players Uniform pieces, at intersections Goals: Territory and Capture Complexity through simplicity Next big AI challenge.
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David Liepmann Professor Cass, Advising Experimental Iterated Competition with Artificially Intelligent Go Agents
The Game and GNU Go • 19x19 board • Two players • Uniform pieces, at intersections • Goals: Territory and Capture • Complexity through simplicity • Next big AI challenge • GNU Go: open source, highly ranked Go AI • 4-phase move decision: • Understand • Candidate moves • Territory evaluation • Strategic evaluation • No fullboard lookahead
Project Structure • Play original and modified against each other • 4 versions: original, 3 modified • 1200 games, 100 each of: • O vs. 1, O vs. 2, O vs. 3 and • 1 vs. 2, 1 vs. 3, 2 vs. 3 and reverse of each • Merge and randomize game results into one list • Analyze list with ELO statistical method • Based on probability to win for that pair of ratings • Simple score method, used with many similar games • Simplification of performance to results, not moves • Only considers win/loss/draw, not point differential ELO System: Rn = Ro + C * (S - Se) whereas: Rn = new rating Ro = old rating S = score Se = expected score C = constant
My Modification(s) • Shared modification: • Surroundedness of disconnected groups • Convex hull “snugness” of fit • Ternary (int) or continuous (float) • Directly affects: escape routes, board comprehension, life-death evaluation • Individuated tweaks • Threshold values for special-case changes to surround variable • Example: opponent groups in the expanded convex hull affect surround_status; if it is overvalued, surround_status needs reduction • Example: special position situations • 1 used ¾, 2 used 2/3, 3 used ½.
Results • Overall: POOR • Guesses: • First-move advantage intensification? • Failure at unknown special case? • ELO analysis useful • Tweaking aspect of project de-emphasized
All is Not Lost • Learned UNIX, Perl, experimental methods, analytical methods, difficulties in contributing to existing large-scale software projects... • Further work: • Locating specific problem case may yield results • Finely-grained variables may still be viable • Broader knowledge of go is vital • Traditional experimental methods Q.E.D.