Function analyze_winner_share

codeclash/analysis/multiplayer/win_share.py:48–150

Compare winner's share between 2-player and multi-player tournaments.

(log_dir: Path, game_pattern: str = "CoreWar.r15.s1000")

def analyze_winner_share(log_dir: Path, game_pattern: str = "CoreWar.r15.s1000"):
    """Compare winner's share between 2-player and multi-player tournaments."""

    # Collect 2-player data
    print("Analyzing 2-player tournaments...")
    winner_shares_2p = []
    for metadata_path in log_dir.rglob(f"*{game_pattern}.p2.*/metadata.json"):
        winner_shares_2p.extend(calculate_winner_share(metadata_path, num_players=2))

    # Collect 6-player data
    print("Analyzing 6-player tournaments...")
    winner_shares_6p = []
    for metadata_path in log_dir.rglob(f"*{game_pattern}.p6.*/metadata.json"):
        winner_shares_6p.extend(calculate_winner_share(metadata_path, num_players=6))

    # Print statistics
    print("\n" + "=" * 70)
    print("WINNER'S SHARE COMPARISON")
    print("=" * 70)

    print("\n2-Player Tournaments:")
    print(f"  Mean: {np.mean(winner_shares_2p):.1f}%")
    print(f"  Median: {np.median(winner_shares_2p):.1f}%")
    print(f"  Range: {np.min(winner_shares_2p):.1f}% - {np.max(winner_shares_2p):.1f}%")
    print(f"  Samples: {len(winner_shares_2p)}")

    print("\n6-Player Tournaments:")
    print(f"  Mean: {np.mean(winner_shares_6p):.1f}%")
    print(f"  Median: {np.median(winner_shares_6p):.1f}%")
    print(f"  Range: {np.min(winner_shares_6p):.1f}% - {np.max(winner_shares_6p):.1f}%")
    print(f"  Samples: {len(winner_shares_6p)}")

    print("\n" + "=" * 70)
    print("KEY INSIGHT")
    print("=" * 70)
    ratio = np.mean(winner_shares_2p) / np.mean(winner_shares_6p)
    print(f"""
In 6-player tournaments, the winner captures only {np.mean(winner_shares_6p):.1f}% of total points
on average, compared to {np.mean(winner_shares_2p):.1f}% in 2-player tournaments.

This means 6-player games are MUCH less dominated by a single winner - victories
are more competitive and less clear-cut ({ratio:.2f}x less dominant).

👉 Bottom line: Multi-player tournaments show MORE COMPETITIVE BALANCE and LESS
   WINNER DOMINANCE than 2-player head-to-head matches.
""")

    # Create visualization
    fig, axes = plt.subplots(1, 2, figsize=(12, 5))

    # Plot 1: Histogram comparison
    ax1 = axes[0]
    ax1.hist(winner_shares_6p, bins=20, alpha=0.7, label="6-Player", color="steelblue", edgecolor="black")
    ax1.hist(winner_shares_2p, bins=20, alpha=0.7, label="2-Player", color="coral", edgecolor="black")
    ax1.axvline(
        np.mean(winner_shares_6p),
        color="steelblue",
        linestyle="--",