Swiftpack.co - Package - troydeville/NEAT-swift

NEAT Implementation With Swift 4

This implementation is based on K.O. Stanley and R. Miikkulainen's paper. http://nn.cs.utexas.edu/downloads/papers/stanley.ec02.pdf

NEAT stands for Neural Evolution of Augmenting Topologies. Just as our brain uses neurons to interpret information, this algorithm searches spaces minimally by creating new connections competitively until a solution is found.

  • If you're creating a Swift executable, you can simply add the package to your app.

To use NEAT-swift inside of an XCode project:

  • Import the package into your project alt text

  • Import the module into your chosen file.

import Neat
  • Create a NEAT network.
let network = Neat(inputs: 2, outputs: 1, population: 300, confFile: nil, multithread: false)

NOTE: "confFile" and "multithread" are not fully functional. "confFile" is not functional mostly because of the inability to edit mutation percentages. "multithread" is functional, but only for 8 threads (i.e. most quad-core processors).

  • Support for other thread amounts will be coming soon. For now, 1 thread or 8 threads are supported.

Typical implementation for a single thread NEAT network (network to be tested until a solution is found or close to it).

let input = [[0.0, 0.0], [0.0, 1.0], [1.0, 0.0], [1.0, 1.0]]
let expected = [[0.0], [1.0], [1.0], [0.0]]

let fitnessGoal = 16.0
var generation = 1

var king: NGenome?

while true {
    for _ in 1...network.populationSize {//testing entire population
        var sumedTotal = 0.0
        // Test the Genome Pool
        for i in 0..<input.count {
            let output = network.run(inputs: input[i], inputCount: inputs, outputCount: outputs)
            for o in 0..<output.count {
                sumedTotal += abs(expected[i][o] - output[o])
        // Assign genome a fitness score from the test.
        let currentGenomeFitness = pow(sqrt(fitnessGoal) - sumedTotal, 2)       
        // conditions
        if currentGenomeFitness > HighestFitness { HighestFitness = currentGenomeFitness }
        // Next
    // Do NEAT here.
    king = network.getKing()
    print("Generation: \(generation)")
    generation += 1
    if king!.fitness >= fitnessGoal*0.99 {
        // Print out the description after the solution is found only.
        // Printing out the description before will result in an unpredictable outcome
} //end

let fitness = network.testNetwork(genome: king!, inputs: input, expected: expected, inputCount: inputs, outputCount: outputs, testType: .distanceSquared, info: true)
print("Fitness: \(fitness)")


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v1.0.0 - Jun 13, 2018

NEAT-swift 1.0!

  • Multi-thread support: 1 or 8 Threads Only.
  • Future Goals:
    • To support any number of threads.
    • Limit species amount. Maybe to cluster species into a fixed amount.