Add: numeric crossover started

src/lib/crossover/numeric/floating/BaseFloatingCrossover.ts

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+/*
+ * @license
+ * Copyright (c) 2019 Cristian Abrante. All rights reserved.
+ * Licensed under the MIT License. See LICENSE in the project root for license information.
+ */
+
+import { Generator } from '../../../generator/utils';
+import { NumericRange } from '../../../individual/numeric/base';
+import { FloatingIndividual } from '../../../individual/numeric/floating';
+import BaseCrossover from '../../base/BaseCrossover';
+import { CrossoverParams, IndividualConstructor } from '../../base/Crossover';
+
+export interface BaseFloatingCrossoverParams extends CrossoverParams<FloatingIndividual, number> {
+  alpha: number;
+}
+
+abstract class BaseFloatingCrossover extends BaseCrossover<FloatingIndividual, number, BaseFloatingCrossoverParams> {
+  private recombinationPoint: number = 0;
+  public cross(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    alpha = 0.5,
+    engine = Generator.DEFAULT_ENGINE,
+  ): FloatingIndividual[] {
+    return this.crossWith(firstParent, secondParent, { engine, alpha, individualConstructor: FloatingIndividual });
+  }
+
+  public crossWith(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    params: BaseFloatingCrossoverParams,
+  ): FloatingIndividual[] {
+    this.generateRecombinationPoint(firstParent.length(), params);
+    this.checkParams(params);
+    return super.crossWith(firstParent, secondParent, params);
+  }
+
+  protected getGenotypeValues(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    params: BaseFloatingCrossoverParams,
+    index: number,
+  ): { first: number; second: number } {
+    const recombinationCondition = this.getRecombinationCondition(index);
+    const firstValue = firstParent.get(index);
+    const secondValue = secondParent.get(index);
+    return {
+      first: recombinationCondition ? firstValue : this.getRecombinationValue(firstValue, secondValue, params),
+      second: recombinationCondition ? secondValue : this.getRecombinationValue(secondValue, firstValue, params),
+    };
+  }
+
+  protected abstract getRecombinationCondition(index: number): boolean;
+
+  protected getRecombinationValue(
+    firstParentValue: number,
+    secondParentValue: number,
+    params: BaseFloatingCrossoverParams,
+  ): number {
+    const { alpha } = params;
+    return alpha * firstParentValue + (1.0 - alpha) * secondParentValue;
+  }
+
+  private checkParams(params: BaseFloatingCrossoverParams) {
+    if (!Generator.probabilityIsValid(params.alpha)) {
+      throw new Error(`BaseFloatingCrossover: alpha of ${params.alpha} is not in range [0.0, 1.0]`);
+    }
+  }
+
+  private generateRecombinationPoint(parentsLength: number, params: BaseFloatingCrossoverParams) {
+    this.recombinationPoint = Generator.generateInteger(new NumericRange(0, parentsLength - 1), params.engine);
+  }
+}

src/lib/crossover/numeric/floating/SimpleArithmeticRecombination.ts

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+/*
+ * @license
+ * Copyright (c) 2019 Cristian Abrante. All rights reserved.
+ * Licensed under the MIT License. See LICENSE in the project root for license information.
+ */
+
+import { Generator } from '../../../generator/utils';
+import { NumericRange } from '../../../individual/numeric/base';
+import { FloatingIndividual } from '../../../individual/numeric/floating';
+import BaseCrossover from '../../base/BaseCrossover';
+import { CrossoverParams, IndividualConstructor } from '../../base/Crossover';
+
+export interface SimpleArithmeticRecombinationParams extends CrossoverParams<FloatingIndividual, number> {
+  alpha: number;
+}
+
+class SimpleArithmeticRecombination extends BaseCrossover<
+  FloatingIndividual,
+  number,
+  SimpleArithmeticRecombinationParams
+> {
+  private recombinationPoint: number = 0;
+
+  public cross(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    individualConstructor: IndividualConstructor<FloatingIndividual, number>,
+    alpha = 0.5,
+    engine = Generator.DEFAULT_ENGINE,
+  ): FloatingIndividual[] {
+    return this.crossWith(firstParent, secondParent, {
+      alpha,
+      engine,
+      individualConstructor,
+    });
+  }
+
+  public crossWith(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    params: SimpleArithmeticRecombinationParams,
+  ): FloatingIndividual[] {
+    this.generateRecombinationPoint(firstParent.length(), params);
+    return super.crossWith(firstParent, secondParent, params);
+  }
+
+  protected getGenotypeValues(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    params: SimpleArithmeticRecombinationParams,
+    index: number,
+  ): { first: number; second: number } {
+    const parentSelectionCondition = index < this.recombinationPoint;
+    const firstValue = firstParent.get(index);
+    const secondValue = secondParent.get(index);
+    return {
+      first: parentSelectionCondition ? firstValue : this.getRecombinedValues(secondValue, firstValue, params),
+      second: parentSelectionCondition ? secondValue : this.getRecombinedValues(firstValue, secondValue, params),
+    };
+  }
+
+  private getRecombinedValues(firstValue: number, secondValue: number, params: SimpleArithmeticRecombinationParams) {
+    return params.alpha * firstValue + (1.0 - params.alpha) * secondValue;
+  }
+
+  private generateRecombinationPoint(parentsLength: number, params: SimpleArithmeticRecombinationParams) {
+    this.recombinationPoint = Generator.generateInteger(new NumericRange(1, parentsLength - 1), params.engine);
+  }
+}

src/lib/crossover/numeric/floating/SingleArithmeticRecombination.ts

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+/*
+ * @license
+ * Copyright (c) 2019 Cristian Abrante. All rights reserved.
+ * Licensed under the MIT License. See LICENSE in the project root for license information.
+ */
+
+import { Generator } from '../../../generator/utils';
+import { NumericRange } from '../../../individual/numeric/base';
+import { FloatingIndividual } from '../../../individual/numeric/floating';
+import BaseCrossover from '../../base/BaseCrossover';
+import { CrossoverParams } from '../../base/Crossover';
+import { SimpleArithmeticRecombinationParams } from './SimpleArithmeticRecombination';
+
+export interface SingleArithmeticRecombinationParams extends CrossoverParams<FloatingIndividual, number> {
+  alpha: number;
+}
+
+class SingleArithmeticRecombination extends BaseCrossover<
+  FloatingIndividual,
+  number,
+  SingleArithmeticRecombinationParams
+> {
+  private recombinationPoint: number = 0;
+
+  public cross(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    ...args: any[]
+  ): FloatingIndividual[] {
+    return [];
+  }
+
+  public crossWith(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    params: SingleArithmeticRecombinationParams,
+  ): FloatingIndividual[] {
+    this.generateRecombinationPoint(firstParent.length(), params);
+    return super.crossWith(firstParent, secondParent, params);
+  }
+
+  protected getGenotypeValues(
+    firstParent: FloatingIndividual,
+    secondParent: FloatingIndividual,
+    params: SingleArithmeticRecombinationParams,
+    index: number,
+  ): { first: number; second: number } {
+    const parentSelectionCondition = index === this.recombinationPoint;
+    const firstValue = firstParent.get(index);
+    const secondValue = secondParent.get(index);
+    return {
+      first: parentSelectionCondition ? firstValue : this.getRecombinedValues(secondValue, firstValue, params),
+      second: parentSelectionCondition ? secondValue : this.getRecombinedValues(firstValue, secondValue, params),
+    };
+  }
+
+  private getRecombinedValues(firstValue: number, secondValue: number, params: SimpleArithmeticRecombinationParams) {
+    return params.alpha * firstValue + (1.0 - params.alpha) * secondValue;
+  }
+
+  private generateRecombinationPoint(parentsLength: number, params: SimpleArithmeticRecombinationParams) {
+    this.recombinationPoint = Generator.generateInteger(new NumericRange(1, parentsLength - 1), params.engine);
+  }
+}