RandomRule.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

package org.apache.mahout.ga.watchmaker.cd.utils;

import org.apache.mahout.ga.watchmaker.cd.CDFitness;
import org.apache.mahout.ga.watchmaker.cd.DataLine;
import org.apache.mahout.ga.watchmaker.cd.Rule;
import org.apache.mahout.ga.watchmaker.cd.hadoop.CDMapper;

import java.util.Random;

public final class RandomRule implements Rule {

  private final Random rng;
  private final int ruleid;
  private final int target;

  public RandomRule(int ruleid, int target, Random rng) {
    this.ruleid = ruleid;
    this.target = target;
    this.rng = rng;
  }

  @Override
  public int classify(DataLine dl) {
    int label = dl.getLabel();
    int prediction = rng.nextInt(2);

    CDFitness fitness = CDMapper.evaluate(target, prediction, label);
    RandomRuleResults.addResult(ruleid, fitness);

    return prediction;
  }
}