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Axelrod Tournament

One model, many views — an interactive exploration of Axelrod's iterated Prisoner's Dilemma tournament, built on the GDS ecosystem.

:octicons-link-external-16: Live Site   :octicons-mark-github-16: Source

Overview

gds-axelrod demonstrates how a single OGS game specification can be projected through six distinct analytical lenses — from narrative storytelling to formal mathematical decomposition to interactive parameter exploration — without simplification or compromise.

The project is a concrete realization of the specification-as-interoperability-layer pattern described in the Interoperability Guide: one compositional model serves as the single source of truth, and multiple independent tools consume it for different purposes.

Architecture

The project splits into two tiers:

Pipeline (Python)                    Site (Vite/JavaScript)
┌──────────────────────┐            ┌──────────────────────────┐
│  OGS game definition │──export──→ │  Canvas Petri dish viz   │
│  gds-sim population  │  (JSON)    │  Mermaid diagrams        │
│  gds-psuu sweeps     │            │  Narrative chapters      │
│  Nash/dominance calc  │            │  Pyodide PSUU sandbox   │
└──────────────────────┘            └──────────────────────────┘

Pipeline: Python data generation using gds-games, gds-sim, gds-psuu, and gds-viz. Produces JSON artifacts consumed by the frontend.

Site: Vite-based JavaScript frontend with Canvas rendering, responsive chapter navigation, and browser-side Python execution via Pyodide.

Six Showcase Views

Each page presents the same underlying Prisoner's Dilemma model through a different analytical lens:

View What It Shows GDS Package
Story Narrative chapters with interactive sandbox simulation Strategy definitions from OGS
Formal Structure Canonical h = f . g decomposition GDSSpec + project_canonical()
Visualizations Mermaid diagrams across 6 view types gds-viz on SystemIR
Simulation Population trajectory tracking over generations gds-sim
Nash Analysis Equilibria and dominance calculations PatternIR from gds-games
PSUU Interactive parameter space exploration gds-psuu via Pyodide

GDS Ecosystem Integration

gds-axelrod exercises four GDS packages together, demonstrating the composability of the ecosystem:

  • gds-domains (gds_domains.games) — defines the game as an OGS pattern, compiles to PatternIR and GDSSpec
  • gds-viz (gds_viz) — renders Mermaid diagrams from the compiled SystemIR
  • gds-sim (gds_sim) — runs population dynamics simulation over iterated tournament rounds
  • gds-analysis (gds_analysis.psuu) — parameter sweeps compiled to WebAssembly via Pyodide for in-browser execution

Key Patterns Demonstrated

Specification as Single Source of Truth

The OGS game definition is written once. Every view — visualization, simulation, equilibrium analysis, parameter exploration — derives from the same specification. No view has a private copy of the model.

Thin Projections

Each analytical tool is a thin projection over the specification:

  • PatternIR → Nash equilibria via Nashpy
  • PatternIR → payoff matrix → tournament simulation
  • SystemIR → Mermaid diagrams via gds-viz
  • GDSSpec → canonical decomposition

Browser-Side Computation

The PSUU page compiles Python (gds-sim + gds-psuu) to WebAssembly via Pyodide, enabling interactive parameter exploration without a backend server.