edu.oregonstate.eecs.mcplan.ensemble.VotingPolicyEnsemble.java Source code

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Here is the source code for edu.oregonstate.eecs.mcplan.ensemble.VotingPolicyEnsemble.java

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/* LICENSE
Copyright (c) 2013-2016, Jesse Hostetler (jessehostetler@gmail.com)
All rights reserved.
    
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    
1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
    
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/**
 * 
 */
package edu.oregonstate.eecs.mcplan.ensemble;

import java.util.ArrayList;

import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.apache.commons.math3.random.RandomGenerator;

import edu.oregonstate.eecs.mcplan.Policy;
import gnu.trove.iterator.TObjectIntIterator;
import gnu.trove.map.TObjectIntMap;
import gnu.trove.map.hash.TObjectIntHashMap;

/**
 * Voted ensemble of policies with random tie-breaking.
 */
public class VotingPolicyEnsemble<S, A> extends Policy<S, A> {
    private final RandomGenerator rng;
    private final ArrayList<Policy<S, A>> Pi;

    public VotingPolicyEnsemble(final RandomGenerator rng, final ArrayList<Policy<S, A>> Pi) {
        this.rng = rng;
        this.Pi = Pi;
    }

    @Override
    public void setState(final S s, final long t) {
        for (final Policy<S, A> pi : Pi) {
            pi.setState(s, t);
        }
    }

    @Override
    public A getAction() {
        final TObjectIntMap<A> counts = new TObjectIntHashMap<A>();
        for (final Policy<S, A> pi : Pi) {
            final A a = pi.getAction();
            counts.adjustOrPutValue(a, 1, 1);
        }

        int max_count = 0;
        final ArrayList<A> candidates = new ArrayList<A>();
        for (final TObjectIntIterator<A> itr = counts.iterator(); itr.hasNext();) {
            itr.advance();
            //         System.out.println( "\t" + itr.key() + " -> " + itr.value() );
            final int c = itr.value();
            if (c > max_count) {
                candidates.clear();
                max_count = c;
                candidates.add(itr.key());
            } else if (c == max_count) {
                candidates.add(itr.key());
            }
        }

        if (candidates.size() == 1) {
            return candidates.get(0);
        } else {
            return candidates.get(rng.nextInt(candidates.size()));
        }
    }

    @Override
    public void actionResult(final S sprime, final double[] r) {
        for (final Policy<S, A> pi : Pi) {
            pi.actionResult(sprime, r);
        }
    }

    @Override
    public String getName() {
        return "VotingPolicyEnsemble";
    }

    @Override
    public int hashCode() {
        final HashCodeBuilder hb = new HashCodeBuilder(5, 11);
        for (final Policy<S, A> pi : Pi) {
            hb.append(pi);
        }
        return hb.toHashCode();
    }

    @Override
    public boolean equals(final Object obj) {
        if (!(obj instanceof VotingPolicyEnsemble<?, ?>)) {
            return false;
        }
        @SuppressWarnings("unchecked")
        final VotingPolicyEnsemble<S, A> that = (VotingPolicyEnsemble<S, A>) obj;
        if (Pi.size() != that.Pi.size()) {
            return false;
        }
        for (int i = 0; i < Pi.size(); ++i) {
            if (!Pi.get(i).equals(that.Pi.get(i))) {
                return false;
            }
        }
        return true;
    }

}