Genetic Algorithm Framework (C++)

A reusable C++ genetic algorithm framework you can embed in any application. It exposes a small, modern C++ API and ships with a rich set of crossover, mutation, and selection operators.

🚀 Features

• Multi-Representation Support: Binary, Real-valued, Integer, and Permutation representations
• Comprehensive Operators: 35+ crossover, mutation, and selection operators
• Benchmark Functions: Rastrigin, Ackley, Schwefel, Rosenbrock, and Sphere optimization problems
• Modern Build System: CMake-based build configuration
• Cross-Platform: Works on Linux, macOS, and Windows
• Multi-Language Support: C++ (primary), Python bindings, and C-compatible interfaces
• Performance Benchmarks: Comprehensive benchmark suite for operators and functions
• Production-Ready: Modern C++17 with smart pointers and RAII

📖 Documentation

• Complete user guide with C++ and Python examples: USER_GUIDE.md
• Complete feature checklist : FEATURE_CHECKLIST.md
• Architecture overview and usage guidance: ARCHITECTURE.md

📁 Project Structure

Genetic_algorithm/
├── CMakeLists.txt              # Main CMake configuration
├── README.md                   # This file
├── include/ga/                 # Public framework headers (installable)
│   ├── config.hpp              # Config, Bounds, Result, Fitness alias
│   └── genetic_algorithm.hpp   # GeneticAlgorithm class and factories
├── src/
│   └── genetic_algorithm.cpp   # Core GA engine implementation
├── examples/
│   └── minimal.cpp             # Tiny example app using the framework
├── simple-ga-test.cc           # Legacy interactive demo (still works)
├── crossover/                  # Crossover operators
│   ├── base_crossover.h/cc     # Base crossover interface
│   ├── one_point_crossover.h/cc
│   ├── two_point_crossover.h/cc
│   ├── uniform_crossover.h/cc
│   ├── blend_crossover.h/cc
│   ├── simulated_binary_crossover.h/cc
│   ├── order_crossover.h/cc
│   ├── partially_mapped_crossover.h/cc
│   ├── cycle_crossover.h/cc
│   └── ... (15+ more operators)
├── mutation/                   # Mutation operators
│   ├── base_mutation.h/cc      # Base mutation interface
│   ├── bit_flip_mutation.h/cc
│   ├── gaussian_mutation.h/cc
│   ├── uniform_mutation.h/cc
│   ├── swap_mutation.h/cc
│   └── ... (10+ more operators)
├── selection-operator/         # Selection methods
│   ├── base_selection.h/cc     # Base selection interface
│   ├── tournament_selection.h/cc
│   ├── roulette_wheel_selection.h/cc
│   ├── rank_selection.h/cc
│   └── ... (5+ more operators)
├── benchmark/                  # Benchmark suite (NEW!)
│   ├── ga_benchmark.h/cc       # Comprehensive benchmarks
│   └── benchmark_main.cc       # Benchmark executable
└── simple-GA-Test/             # Test suite and fitness functions
    ├── fitness-function.h      # Fitness function declarations
    ├── fitness-fuction.cc      # Fitness function implementations
    └── README.md              # Detailed test documentation

🛠️ Building with CMake

Prerequisites

• CMake (version 3.16 or higher)
• C++17 compatible compiler:
  • GCC 7+ (Linux/macOS)
  • Clang 5+ (Linux/macOS)
  • MSVC 2017+ (Windows)

Quick Start

Using Build Script (Recommended)

# Clone or navigate to the project directory
cd test-ga

# Build and run in one command
./build.sh --run

# Or build only
./build.sh

Using CMake Directly

cd Genetic_algorithm

# Create build directory
mkdir build && cd build

# Configure with CMake
cmake ..

# Build the project
cmake --build .

# Run the legacy demo
./bin/simple_ga_test

Advanced Build Options

# Debug build with verbose output
cmake -DCMAKE_BUILD_TYPE=Debug ..
cmake --build . --verbose

# Release build with optimizations
cmake -DCMAKE_BUILD_TYPE=Release ..
cmake --build . -j$(nproc)

# Install to system (optional)
sudo cmake --build . --target install

Build Script

The project includes a convenient build script (build.sh) that automates the build process:

# Basic build
./build.sh

# Build with options
./build.sh --debug --run --verbose

# Clean build
./build.sh --clean

# Install to system
./build.sh --install

CMake Targets

• genetic_algorithm: Static library (the framework)
• simple-ga-test: Interactive demo executable
• run: Build and run the GA test
• clean-results: Remove output files
• install: Install to system

# Use custom targets
cmake --build . --target run
cmake --build . --target clean-results

🎯 Using the framework in your code

The public API is in include/ga. Example:

#include <ga/genetic_algorithm.hpp>
#include <cmath>

static double rastrigin(const std::vector<double>& x) {
  const double A = 10.0;
  double sum = A * x.size();
  for (double xi : x) sum += xi*xi - A*std::cos(2*M_PI*xi);
  // convert minimization to maximization fitness
  return 1000.0 / (1.0 + sum);
}

int main() {
  ga::Config cfg;
  cfg.populationSize = 60;
  cfg.generations = 100;
  cfg.dimension = 10;
  cfg.bounds = {-5.12, 5.12};

  ga::GeneticAlgorithm alg(cfg);
  ga::Result res = alg.run(rastrigin);
}

You can also compile and run the ready-made example:

cmake --build build -j
./build/examples/minimal

NSGA-II minimal example:

cmake --build build -j
./build/examples/ga-nsga2-minimal

High-level optimizer API example:

cmake --build build -j
./build/examples/ga-optimizer-minimal

NSGA-III sanity test:

cmake --build build --target nsga3-sanity
./build/tests/nsga3-sanity

To customize operators:

#include <ga/genetic_algorithm.hpp>

auto alg = ga::GeneticAlgorithm(cfg);
alg.setCrossoverOperator(ga::makeTwoPointCrossover());
alg.setMutationOperator(ga::makeUniformMutation());

C API (Baseline Wrapper)

The project includes a C-compatible API in include/ga/c_api.h.

Key C API additions:

• ga_validate_config(...) for pre-run argument checks
• ga_history_length(...), ga_best_history(...), ga_avg_history(...) for convergence history export

#include <ga/c_api.h>

static double sphere_fitness(const double* genes, int length, void* user_data) {
  (void)user_data;
  double sum = 0.0;
  for (int i = 0; i < length; ++i) {
    sum += genes[i] * genes[i];
  }
  return 1000.0 / (1.0 + sum);
}

int main(void) {
  ga_config_c cfg = {60, 100, 10, 0.8, 0.1, -5.12, 5.12, 0.05, 42};
  if (ga_validate_config(&cfg) != GA_STATUS_OK) {
    return 1;
  }

  ga_handle* h = ga_create(&cfg);
  if (!h) {
    return 1;
  }

  if (ga_run(h, sphere_fitness, 0) != GA_STATUS_OK) {
    ga_destroy(h);
    return 1;
  }

  double best = ga_best_fitness(h);

  int n = ga_history_length(h);
  double history[1024];
  if (n > 0 && n <= 1024) {
    (void)ga_best_history(h, history, n);
  }

  ga_destroy(h);
  (void)best;
  return 0;
}

NSGA-II Utilities (C++ Core)

NSGA-II helper APIs are available in include/ga/algorithms/moea/nsga2.hpp:

• non-dominated sorting
• crowding distance
• callback-based generation loop (run(...))

NSGA-III helper APIs are available in include/ga/moea/nsga3.hpp:

• Das-Dennis reference point generation
• reference-point environmental selection niching with intercept-based normalization

High-level optimizer methods in include/ga/api/optimizer.hpp now include:

• optimizeMultiObjective(...) (NSGA-II)
• optimizeMultiObjectiveNsga3(...)

Distributed evaluation backends in include/ga/evaluation/distributed_executor.hpp:

• LocalDistributedExecutor (threaded local backend)
• ProcessDistributedExecutor (true multi-process backend on POSIX)

Python bindings (python/ga_bindings.cpp) also expose:

• NSGA-III objective-space utilities (Nsga3, nsga3_reference_points, nsga3_environmental_select_indices)
• checkpoint JSON API (CheckpointState, checkpoint_save_json, checkpoint_load_json)

Interactive Mode (Recommended)

./bin/simple_ga_test

The program will guide you through:

1. Representation selection (binary, real_valued, integer, permutation)
2. Operator validation against chosen representation
3. Automatic configuration of compatible operators

Command Line Testing

Real-Valued Optimization

echo -e "real_valued\nblend\ngaussian\ntournament" | ./bin/simple_ga_test

Binary Optimization

echo -e "binary\nuniform\nbit_flip\ntournament" | ./bin/simple_ga_test

Integer Optimization

echo -e "integer\narithmetic\nrandom_resetting\ntournament" | ./bin/simple_ga_test

Permutation Problems

echo -e "permutation\norder_crossover\nswap\ntournament" | ./bin/simple_ga_test

C API Sanity Test

cmake --build build --target c-api-sanity
./build/tests/c-api-sanity

Feature Foundation Sanity Test

cmake --build build --target features-foundation-sanity
./build/tests/features-foundation-sanity

Process Distributed Backend Sanity Test

cmake --build build --target process-distributed-sanity
./build/tests/process-distributed-sanity

🔧 Configuration

The framework uses ga::Config:

struct Bounds { double lower, upper; };
struct Config {
  int populationSize = 50;
  int generations = 100;
  int dimension = 10;
  double crossoverRate = 0.8;
  double mutationRate = 0.1;
  Bounds bounds{-5.12, 5.12};
  double eliteRatio = 0.05; // 5% elites
  unsigned seed = 0;        // 0 -> random
};

📊 Supported Representations & Operators

Binary Representation

• Crossovers: One-point, Two-point, Uniform
• Mutations: Bit-flip
• Use Cases: Feature selection, binary optimization

Real-Valued Representation

• Crossovers: Arithmetic, Blend (BLX-α), SBX, One-point, Two-point, Uniform
• Mutations: Gaussian, Uniform
• Use Cases: Continuous function optimization, parameter tuning

Integer Representation

• Crossovers: One-point, Two-point, Uniform, Arithmetic
• Mutations: Random resetting, Creep
• Use Cases: Discrete optimization, scheduling problems

Permutation Representation

• Crossovers: Order crossover (OX), Partially mapped crossover (PMX), Cycle crossover
• Mutations: Swap, Insert, Scramble, Inversion
• Use Cases: Traveling salesman problem, job scheduling

🧪 Benchmark Functions

The framework includes 5 standard optimization test functions:

1. Sphere Function: Simple unimodal function (baseline)
2. Rastrigin Function: Highly multimodal with many local optima
3. Ackley Function: One global minimum with many local minima
4. Schwefel Function: Deceptive function with global optimum far from local optima
5. Rosenbrock Function: Narrow valley, challenging for optimization

🔬 Running Benchmarks

The framework includes a comprehensive benchmark suite that tests:

• Operator Performance: Speed of crossover, mutation, and selection operators
• Function Optimization: Convergence quality on test functions
• Scalability: Performance vs. population size and problem dimension

Quick Start

# Build the benchmark executable
cmake --build build

# Run all benchmarks
./build/bin/ga-benchmark --all

# Run specific benchmark categories
./build/bin/ga-benchmark --operators      # Test operator performance
./build/bin/ga-benchmark --functions      # Test function optimization
./build/bin/ga-benchmark --scalability    # Test scalability

# Customize benchmark iterations
./build/bin/ga-benchmark --operators --iterations 1000

# Export results to CSV
./build/bin/ga-benchmark --all --csv

# Show help
./build/bin/ga-benchmark --help

Benchmark Results

Operator Performance (typical results on modern CPU):

Operator Category	Representative	Throughput
Binary Crossover	TwoPointCrossover	2M ops/sec
Real Crossover	BlendCrossover (BLX-α)	5M ops/sec
Permutation Crossover	OrderCrossover (OX)	869K ops/sec
Binary Mutation	BitFlipMutation	1.1M ops/sec
Real Mutation	GaussianMutation	6.6M ops/sec
Permutation Mutation	SwapMutation	20M ops/sec
Selection	TournamentSelection	181K ops/sec

Function Optimization (convergence times):

Function	Generations	Time (ms)	Best Fitness
Sphere	100	~1	>500
Rastrigin	200	~5	>60
Ackley	150	~4	>60
Schwefel	200	~7	Variable
Rosenbrock	300	~8	>200

Results will vary based on hardware, problem configuration, and random seed.

Understanding Benchmark Output

The benchmark tool generates:

• Console output: Real-time progress and summary statistics
• benchmark_results.txt: Detailed results with all metrics
• benchmark_results.csv: Machine-readable format (with --csv flag)

🏗️ Architecture & Efficiency

For a detailed analysis of the framework's architecture, efficiency, and usability across C++, Python, and C, see ARCHITECTURE.md.

Key Highlights:

• ⚡ Performance: Native C++17 with zero-overhead abstractions
• 🔧 Extensible: Easy to add custom operators and fitness functions
• 🌐 Multi-language: C++ core with Python bindings
• 📊 Validated: Comprehensive benchmark suite included
• 🧪 Tested: Multiple test programs and sanity checks

🔍 Development

Adding New Operators

1. Create header and implementation files in the appropriate directory
2. Inherit from the base operator class
3. Implement required virtual methods
4. Optionally expose convenience factories alongside ga::make* helpers

Adding New Fitness Functions

1. Add declaration to simple-GA-Test/fitness-function.h
2. Implement in simple-GA-Test/fitness-fuction.cc
3. Add to the GAConfig::FunctionType enum
4. Update the fitness function selection logic

Building for Development

# Debug build with symbols
cmake -DCMAKE_BUILD_TYPE=Debug ..
cmake --build .

# Run with debug output
./bin/simple_ga_test

📝 Output

The program generates:

• Console output: Progress information and final results
• ga_results.txt: Detailed results including:
  • Best fitness values per generation
  • Average fitness values
  • Best individual's chromosome
  • Optimization statistics

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable
5. Submit a pull request

📄 License

This project is open source. Please check individual files for license information.

🆘 Troubleshooting

Common Issues

CMake not found:

# Ubuntu/Debian
sudo apt install cmake

# macOS
brew install cmake

# Windows
# Download from https://cmake.org/download/

Compiler not found:

# Ubuntu/Debian
sudo apt install build-essential

# macOS
xcode-select --install

Build errors:

# Clean and rebuild
rm -rf build
mkdir build && cd build
cmake ..
cmake --build .

Getting Help

• Check the detailed documentation in simple-GA-Test/README.md
• Review the CMake configuration in CMakeLists.txt
• Examine the source code for implementation details