com.cloudera.oryx.ml.param.ContinuousAround.java Source code

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Here is the source code for com.cloudera.oryx.ml.param.ContinuousAround.java

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/*
 * Copyright (c) 2014, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. 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
 *
 * This software 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 com.cloudera.oryx.ml.param;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import com.google.common.base.Preconditions;
import org.apache.commons.math3.random.RandomDataGenerator;

final class ContinuousAround implements HyperParamValues<Double>, Serializable {

    private final double around;
    private final double step;

    ContinuousAround(double around, double step) {
        Preconditions.checkArgument(step > 0.0);
        this.around = around;
        this.step = step;
    }

    @Override
    public List<Double> getTrialValues(int num) {
        Preconditions.checkArgument(num > 0);
        if (num == 1) {
            return Collections.singletonList(around);
        }
        List<Double> values = new ArrayList<>(num);
        double value = around - ((num - 1.0) / 2.0) * step;
        for (int i = 0; i < num; i++) {
            values.add(value);
            value += step;
        }
        // Make sure middle value is exact
        if (num % 2 != 0) {
            values.set(num / 2, around);
        }
        return values;
    }

    /**
     * @param rdg random number generator to use
     * @return a hyperparameter value chosen from Normal(around, step)
     */
    @Override
    public Double getRandomValue(RandomDataGenerator rdg) {
        return rdg.nextGaussian(around, step);
    }

    /**
     * @return {@code Long.MIN_VALUE}
     */
    @Override
    public long getNumDistinctValues() {
        return Long.MAX_VALUE;
    }

    @Override
    public String toString() {
        return "ContinuousAround[..." + getTrialValues(3) + "...]";
    }

}