Position Evaluationin Computer Go

Martin Muller

Dept. of Computer Science and Information Engineering National Dong Hwa UniversityReporter ： Lo Jung-Yun

Outline• Introduction

• Exact Evaluation in Explorer

• Heuristic Territory Evaluation in Explorer

• Full-Board Evaluation

• Open Problem and Future Work

• Project Progress

Introduction• Describe the position evaluation

methods used in Explorer

• Two different approach–Modularized heuristic evaluation using

the concept of zones– An emphasis on exact evaluation

methods for several types of local situations

Exact Evaluation in Explorer• Safe Territory– Both static rules and method based on l

ocal search for detecting groups of blocks is safe

• Capturing Race (semeai)– Also by static rules

• End Game Area

Heuristic Territory Evaluation in Explorer

• Distinguish several different types of points

• Divider and potential divider• Zone– Safe zone– Potential zone– Threatened zone– Unused zone

• Point outside the territory– Near points– Junction points– Far-away points

Heuristic Territory Evaluation in Explorer

• Divider and potential divider– Computed using pattern matching

• Safe zone– Are surrounded only by stones and dividers,

and the interior is strongly controlled by stones

• Potential zone– Weaker than safe territory, either because part

of the boundary is only a potential divider, or because the control over the inside is not strong enough

• Threatened zone– Weaker than potential zone

• Unused zone– Contain strong opponent groups

Different Types of Points• Divider and Potential Divider– Using pattern matching

Different Types of Points• Zone, potential zone, threatened

zone, and unused zone

Point Outside The Territory• Divider-adjusted distances

Point Outside The TerritoryFar-away Points are at least distance 5 away from both

player

Junction Points are less than 5 and which the difference of distance to black and white is at most 1

Near Remaining points are either black or white

Full-Board Evaluation• Weight setting

Safe territory ±1

Potential territory ±½

Near point ±0.2

Junction point and far-away point 0

Open Problems and Future Work

• Maximize the chance of winning, not for score

Project progress2005.07 08 09 10 11 12 2006.01 02

A

B

C

D

E

F

A. 確定明確的方向及題目B. 充實基本知識C. 規劃系統及收集資訊D. 系統實作E. 驗收及改善F. 論文撰寫

Project progress• Function– Open *.sgf file (using Neko’s parser)– Put stones on the board

• Running– Check capture– Some data structure • Stone string• Stone group