Build autonomous game-playing agents using AI and reinforcement learning. Covers game environments, agent decision-making, strategy development, and performance optimization...
Build sophisticated game-playing agents that learn strategies, adapt to opponents, and master complex games through AI and reinforcement learning.
Autonomous game agents combine:
Run example agents with:
# Rule-based agent
python examples/rule_based_agent.py
# Minimax with alpha-beta pruning
python examples/minimax_agent.py
# Monte Carlo Tree Search
python examples/mcts_agent.py
# Q-Learning agent
python examples/qlearning_agent.py
# Chess engine
python examples/chess_engine.py
# Game theory analysis
python scripts/game_theory_analyzer.py
# Benchmark agents
python scripts/agent_benchmark.py
Use predefined rules and heuristics. See full implementation in examples/rule_based_agent.py.
Key Concepts:
Usage Example:
from examples.rule_based_agent import RuleBasedGameAgent
agent = RuleBasedGameAgent(difficulty="hard")
best_move = agent.decide_action(game_state)
Optimal decision-making for turn-based games. See examples/minimax_agent.py.
Key Concepts:
Performance Characteristics:
Usage Example:
from examples.minimax_agent import MinimaxGameAgent
agent = MinimaxGameAgent(max_depth=6)
best_move = agent.get_best_move(game_state)
Probabilistic game tree exploration. Full implementation in examples/mcts_agent.py.
Key Concepts:
The UCT Formula: UCT = (child_value / child_visits) + c * sqrt(ln(parent_visits) / child_visits)
Usage Example:
from examples.mcts_agent import MCTSAgent
agent = MCTSAgent(iterations=1000, exploration_constant=1.414)
best_move = agent.get_best_move(game_state)
Learn through interaction with environment. See examples/qlearning_agent.py.
Key Concepts:
Hyperparameters:
Usage Example:
from examples.qlearning_agent import QLearningAgent
agent = QLearningAgent(learning_rate=0.1, discount_factor=0.99, epsilon=0.1)
action = agent.get_action(state)
agent.update_q_value(state, action, reward, next_state)
agent.decay_epsilon() # Reduce exploration over time
Create game environments compatible with agents. See examples/game_environment.py for base classes.
Key Methods:
reset(): Initialize game statestep(action): Execute action, return (next_state, reward, done)get_legal_actions(state): List valid movesis_terminal(state): Check if game is overrender(): Display game stateStandard interface for game environments:
import gym
# Create environment
env = gym.make('CartPole-v1')
# Initialize
state = env.reset()
# Run episode
done = False
while not done:
action = agent.get_action(state)
next_state, reward, done, info = env.step(action)
agent.update(state, action, reward, next_state)
state = next_state
env.close()
Full chess implementation in examples/chess_engine.py. Requires: pip install python-chess
Features:
Quick Example:
from examples.chess_engine import ChessAgent
agent = ChessAgent()
result, moves = agent.play_game()
print(f"Game result: {result} in {moves} moves")
Extend examples/game_environment.py with pygame rendering:
from examples.game_environment import PygameGameEnvironment
class MyGame(PygameGameEnvironment):
def get_initial_state(self):
# Return initial game state
pass
def apply_action(self, state, action):
# Execute action, return new state
pass
def calculate_reward(self, state, action, next_state):
# Return reward value
pass
def is_terminal(self, state):
# Check if game is over
pass
def draw_state(self, state):
# Render using pygame
pass
game = MyGame()
game.render()
All strategy implementations are in examples/strategy_modules.py.
Pre-computed best moves for game openings. Load from PGN files or opening databases.
OpeningBook Features:
Usage:
from examples.strategy_modules import OpeningBook
book = OpeningBook()
if book.in_opening(game_state):
move = book.get_opening_move(game_state)
Pre-computed endgame solutions with optimal moves and distance-to-mate.
Features:
Usage:
from examples.strategy_modules import EndgameTablebase
tablebase = EndgameTablebase()
if tablebase.in_tablebase(game_state):
move = tablebase.get_best_endgame_move(game_state)
dtm = tablebase.get_endgame_distance(game_state)
Combine different agents for different game phases using AdaptiveGameAgent.
Strategy Selection:
Usage:
from examples.strategy_modules import AdaptiveGameAgent
from examples.minimax_agent import MinimaxGameAgent
agent = AdaptiveGameAgent(
opening_book=book,
middlegame_engine=MinimaxGameAgent(max_depth=6),
endgame_tablebase=tablebase
)
move = agent.decide_action(game_state)
phase_info = agent.get_phase_info(game_state)
Combine multiple strategies with priority ordering using CompositeStrategy.
Usage:
from examples.strategy_modules import CompositeStrategy
composite = CompositeStrategy([
opening_strategy,
endgame_strategy,
default_search_strategy
])
move = composite.get_move(game_state)
active = composite.get_active_strategy(game_state)
All optimization utilities are in scripts/performance_optimizer.py.
Cache evaluated positions to avoid re-computation. Especially effective with alpha-beta pruning.
How it works:
Bound Types:
Usage:
from scripts.performance_optimizer import TranspositionTable
tt = TranspositionTable(max_size=1000000)
# Store evaluation
tt.store(position_hash, depth=6, score=150, flag='exact')
# Lookup
score = tt.lookup(position_hash, depth=6)
hit_rate = tt.hit_rate()
Track moves that cause cutoffs at similar depths for move ordering improvement.
Concept:
Usage:
from scripts.performance_optimizer import KillerHeuristic
killers = KillerHeuristic(max_depth=20)
# When a cutoff occurs
killers.record_killer(move, depth=5)
# When ordering moves
killer_list = killers.get_killers(depth=5)
is_killer = killers.is_killer(move, depth=5)
Parallelize game tree search across multiple threads.
Usage:
from scripts.performance_optimizer import ParallelSearchCoordinator
coordinator = ParallelSearchCoordinator(num_threads=4)
# Parallel move evaluation
scores = coordinator.parallel_evaluate_moves(moves, evaluate_func)
# Parallel minimax
best_move, score = coordinator.parallel_minimax(root_moves, minimax_func)
coordinator.shutdown()
Track and analyze search performance with SearchStatistics.
Metrics:
Usage:
from scripts.performance_optimizer import SearchStatistics
stats = SearchStatistics()
# During search
stats.record_node()
stats.record_cutoff()
stats.record_cache_hit()
# Analysis
print(stats.summary())
print(f"Pruning efficiency: {stats.pruning_efficiency():.1f}%")
Full implementation in scripts/game_theory_analyzer.py.
Find optimal mixed strategy solutions for 2-player games.
Pure Strategy Nash Equilibria: A cell is a Nash equilibrium if it's a best response for both players.
Mixed Strategy Nash Equilibria: Players randomize over actions. For 2x2 games, use indifference conditions.
Usage:
from scripts.game_theory_analyzer import GameTheoryAnalyzer, PayoffMatrix
import numpy as np
# Create payoff matrix
p1_payoffs = np.array([[3, 0], [5, 1]])
p2_payoffs = np.array([[3, 5], [0, 1]])
matrix = PayoffMatrix(
player1_payoffs=p1_payoffs,
player2_payoffs=p2_payoffs,
row_labels=['Strategy A', 'Strategy B'],
column_labels=['Strategy X', 'Strategy Y']
)
analyzer = GameTheoryAnalyzer()
# Find pure Nash equilibria
equilibria = analyzer.find_pure_strategy_nash_equilibria(matrix)
# Find mixed Nash equilibrium (2x2 only)
p1_mixed, p2_mixed = analyzer.calculate_mixed_strategy_2x2(matrix)
# Expected payoff
payoff = analyzer.calculate_expected_payoff(p1_mixed, p2_mixed, matrix, player=1)
# Zero-sum analysis
if matrix.is_zero_sum():
minimax = analyzer.minimax_value(matrix)
maximin = analyzer.maximin_value(matrix)
Analyze coalitional games where players can coordinate.
Shapley Value:
Core:
Usage:
from scripts.game_theory_analyzer import CooperativeGameAnalyzer
coop = CooperativeGameAnalyzer()
# Define payoff function for coalitions
def payoff_func(coalition):
# Return total value of coalition
return sum(player_values[p] for p in coalition)
players = ['Alice', 'Bob', 'Charlie']
# Calculate Shapley values
shapley = coop.calculate_shapley_value(payoff_func, players)
print(f"Alice's fair share: {shapley['Alice']}")
# Find core allocation
core = coop.calculate_core(payoff_func, players)
is_stable = coop.is_core_allocation(core, payoff_func, players)
Complete benchmarking toolkit in scripts/agent_benchmark.py.
Run round-robin or elimination tournaments between agents.
Usage:
from scripts.agent_benchmark import GameAgentBenchmark
benchmark = GameAgentBenchmark()
# Run tournament
results = benchmark.run_tournament(agents, num_games=100)
# Compare two agents
comparison = benchmark.head_to_head_comparison(agent1, agent2, num_games=50)
print(f"Win rate: {comparison['agent1_win_rate']:.1%}")
Calculate agent strength using standard rating systems.
Elo Rating:
Glicko-2 Rating:
Usage:
# Elo ratings
elo_ratings = benchmark.evaluate_elo_rating(agents, num_games=100)
# Glicko-2 ratings
glicko_ratings = benchmark.glicko2_rating(agents, num_games=100)
# Strength relative to baseline
strength = benchmark.rate_agent_strength(agent, baseline_agents, num_games=20)
Evaluate agent quality on test positions.
Usage:
# Get performance profile
profile = benchmark.performance_profile(agent, test_positions, time_limit=1.0)
print(f"Accuracy: {profile['accuracy']:.1%}")
print(f"Avg move quality: {profile['avg_move_quality']:.2f}")