io.github.ericmedvet.jgea.problem.synthetic.IntOneMax Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jgea.problem Show documentation

Problem (benchmarks and templates) for jgea.

The newest version!

/*-
 * ========================LICENSE_START=================================
 * jgea-problem
 * %%
 * Copyright (C) 2018 - 2024 Eric Medvet
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =========================LICENSE_END==================================
 */

package io.github.ericmedvet.jgea.problem.synthetic;

import io.github.ericmedvet.jgea.core.problem.ComparableQualityBasedProblem;
import io.github.ericmedvet.jgea.core.problem.ProblemWithExampleSolution;
import io.github.ericmedvet.jgea.core.representation.sequence.integer.IntString;
import java.util.Collections;
import java.util.function.Function;

public class IntOneMax
    implements ComparableQualityBasedProblem, ProblemWithExampleSolution {

  private final int p;
  private final int upperBound;
  private final Function fitnessFunction;

  public IntOneMax(int p, int upperBound) {
    this.p = p;
    this.upperBound = upperBound;
    fitnessFunction = s -> {
      if (s.size() != p) {
        throw new IllegalArgumentException("Wrong input size: %d expected, %d found".formatted(p, s.size()));
      }
      return s.genes().stream().mapToInt(n -> n).average().orElse(0d) / (double) s.size();
    };
  }

  @Override
  public IntString example() {
    return new IntString(Collections.nCopies(p, 0), 0, upperBound);
  }

  @Override
  public Function qualityFunction() {
    return fitnessFunction;
  }
}