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  • License MIT

Multiprocessing genetic algorithm implementation library

Package Exports

  • genetic-search
  • genetic-search/es/index.js
  • genetic-search/lib/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (genetic-search) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Multiprocessing Genetic Algorithm Implementation for TypeScript

npm npm Coverage Status Build and test Minified Size License: MIT

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Setup

npm i genetic-search

Usage example

Let's get a max value of the parabola: y = -(x-12)^2 - 3.

import type {
  GeneticSearchConfig,
  GeneticSearchStrategyConfig,
} from "genetic-search";
import {
  GeneticSearch,
  SimpleMetricsCache,
} from "genetic-search";

const config: GeneticSearchConfig = {
  populationSize: 100,
  survivalRate: 0.5,
  crossoverRate: 0.5,
};

const strategies: GeneticSearchStrategyConfig<ParabolaArgumentGenome> = {
  populate: new ParabolaPopulateStrategy(),
  metrics: new ParabolaMultiprocessingMetricsStrategy({
    poolSize: 4,
    task: async (data) => [-((data[0] - 12)**2) - 3],
    onTaskResult: () => void 0,
  }),
  fitness: new ParabolaMaxValueFitnessStrategy(),
  mutation: new ParabolaMutationStrategy(),
  crossover: new ParabolaCrossoverStrategy(),
  cache: new SimpleMetricsCache(),
}

const search = new GeneticSearch(config, strategies);

expect(search.partitions).toEqual([50, 25, 25]);

await search.fit({
  generationsCount: 100,
  beforeStep: () => void 0,
  afterStep: () => void 0,
});

const bestGenome = search.bestGenome;
console.log('Best genome:', bestGenome);

Strategies implementation:

import type {
  BaseGenome,
  BaseMutationStrategyConfig,
  CrossoverStrategyInterface,
  FitnessStrategyInterface,
  GenerationFitnessColumn,
  GenerationMetricsMatrix,
  IdGeneratorInterface,
  MultiprocessingMetricsStrategyConfig,
  PopulateStrategyInterface,
} from "genetic-search";
import {
  BaseMultiprocessingMetricsStrategy,
  BaseMutationStrategy,
} from "genetic-search";

export type ParabolaArgumentGenome = BaseGenome & {
  id: number;
  x: number;
}

export type ParabolaTaskConfig = [number];

export class ParabolaPopulateStrategy implements PopulateStrategyInterface<ParabolaArgumentGenome> {
  populate(size: number, idGenerator: IdGeneratorInterface<ParabolaArgumentGenome>): ParabolaArgumentGenome[] {
    const result: ParabolaArgumentGenome[] = [];
    for (let i=0; i<size; ++i) {
      result.push({ id: idGenerator.nextId(), x: Math.random() * 200 - 100 });
    }
    return result;
  }
}

export class ParabolaMutationStrategy extends BaseMutationStrategy<ParabolaArgumentGenome, BaseMutationStrategyConfig> {
  constructor() {
    super({ probability: 1 });
  }

  mutate(genome: ParabolaArgumentGenome, newGenomeId: number): ParabolaArgumentGenome {
    return { x: genome.x + Math.random() * 10 - 5, id: newGenomeId };
  }
}

export class ParabolaCrossoverStrategy implements CrossoverStrategyInterface<ParabolaArgumentGenome> {
  cross(lhs: ParabolaArgumentGenome, rhs: ParabolaArgumentGenome, newGenomeId: number): ParabolaArgumentGenome {
    return { x: (lhs.x + rhs.x) / 2, id: newGenomeId };
  }
}

export class ParabolaMultiprocessingMetricsStrategy extends BaseMultiprocessingMetricsStrategy<ParabolaArgumentGenome, MultiprocessingMetricsStrategyConfig<ParabolaTaskConfig>, ParabolaTaskConfig> {
  protected createTaskInput(genome: ParabolaArgumentGenome): ParabolaTaskConfig {
    return [genome.x];
  }
}

export class ParabolaMaxValueFitnessStrategy implements FitnessStrategyInterface {
  score(results: GenerationMetricsMatrix): GenerationFitnessColumn {
    return results.map((result) => result[0]);
  }
}

Unit testing

npm i
npm run test

License

Genetic Search TS is licensed under the MIT License.