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2019-06-06 15:21:15 +03:00
/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://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.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
package org.deeplearning4j.rl4j.policy;
import lombok.AllArgsConstructor;
import org.deeplearning4j.rl4j.network.dqn.IDQN;
import org.deeplearning4j.rl4j.space.Encodable;
import org.nd4j.linalg.api.ndarray.INDArray;
import java.util.Random;
import static org.nd4j.linalg.ops.transforms.Transforms.exp;
/**
* @author rubenfiszel (ruben.fiszel@epfl.ch) on 8/10/16.
*
* Boltzmann exploration is a stochastic policy wrt to the
* exponential Q-values as evaluated by the dqn model.
*/
@AllArgsConstructor
public class BoltzmannQ<O extends Encodable> extends Policy<O, Integer> {
final private IDQN dqn;
final private Random rd = new Random(123);
public IDQN getNeuralNet() {
return dqn;
}
public Integer nextAction(INDArray input) {
INDArray output = dqn.output(input);
INDArray exp = exp(output);
double sum = exp.sum(1).getDouble(0);
double picked = rd.nextDouble() * sum;
for (int i = 0; i < exp.columns(); i++) {
if (picked < exp.getDouble(i))
return i;
}
return -1;
}
}