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This paper presents the Open Boundary Safety-of-Territory Solver 2.0 for the game of Go, which estimates the safety of open boundary territories. The solver includes new features such as customized search goals, multi-searches, and integration with full-board play. Experimental results show the solver's effectiveness in evaluating the safety status of open boundary areas. Future work includes implementing a flexible time control scheme, integrating other tactical solvers, and measuring playing strength improvements.
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An Open Boundary Safety-of-Territory Solver for the Game of Go Author: Xiaozhen Niu, Martin Mueller Dept of Computing Science University of Alberta Presented by: Xiaozhen Niu
Outline • Introduction • Open Boundary Safety-of-Territory Solver • Forward Pruning Techniques • Experimental Results • Conclusions and Future Work
Introduction • Problem: In real games, most territories are not fully enclosed • Safety solver 1.0 has several restrictions: • The region has to be completely enclosed • Does not consider external liberties • Goal: estimating the safety of open boundary territories!
Example • White plays first
Open Boundary Safety-of-Territory Solver • New features of safety solver 2.0 • Input parameters and goal setting • Board partitioning • Multiple searches for related goals
New Features • Safety solver 2.0 has following new features: • Search goals customized by different parameters • Multi-searches to provide solutions for different goals • Integration with full-board play in Explorer
Input parameters (1) • A set of points (area) • The color of the defender and attacker • The color of the first player • Boundary safe or territory safe?
Input parameters (2) • Handle Seki • External Liberties • Who is the ko winner?
Search Goal Setting • Safety solver 2.0 concentrates on proving area safe locally • Does not consider connection problems • Default search goal: • Prove territory safe • Handle seki • Count external liberties • No ko winner needs to be set initially
Board Partitioning • Zone computing • Zone merging
Zone Computing • Use heuristic territory evaluation to partition the board into zones • Zones are computed by using dividers, potential dividers
Zone Merging • Two zones are related if they share one or more common boundary blocks • Safety solver 2.0 extends the merging algorithm for enclosed zones by dealing with dividers
Multiple Searches for Related Goals • Switching which player plays first
Multiple Searches for Related Goals (2) • Determining when external liberties affect the safety status of an area
Integration with Explorer • Generate defending or invading move for zones • Set move values by heuristics
Forward Pruning Techniques • Two techniques for the defender: • External moves • Inner eyes
External Moves • In a 12 interior points zone. Generate 20 moves for the attacker and 16 moves for the defender
Inner Eyes • Inner eyes can be pruned for the defender
Experimental Results • Two test sets. • Set one: most from classic Guan Zi Pu. 60 main problem and 60 modified problems that has some external liberties added • Set two: 20 problems from computer game play records
Test Set 1: Correctness Test • Four Examples from set 1
Test Set 2: Game Play Test • Goal: to test whether Explorer enhanced by the safety solver 2.0 is able to play the correct defending or invading move
Conclusions • Safety solver 2.0 can provide evaluations for the safety status of open boundary areas • Major limitation: size of the open area (current: 15)
Future Work: • Flexible time control scheme using heuristics to select suitable problems to solve • Get best try move • Integrate other tactical solvers • Measure playing strength improvements