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

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Here is the source code for com.cloudera.oryx.ml.param.DiscreteRange.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.Arrays;
import java.util.Collections;
import java.util.List;

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

final class DiscreteRange implements HyperParamValues<Integer>, Serializable {

    private final int min;
    private final int max;

    DiscreteRange(int min, int max) {
        Preconditions.checkArgument(min <= max);
        this.min = min;
        this.max = max;
    }

    @Override
    public List<Integer> getTrialValues(int num) {
        Preconditions.checkArgument(num > 0);
        if (max == min) {
            return Collections.singletonList(min);
        }
        if (num == 1) {
            return Collections.singletonList((max + min) / 2);
        }
        if (num == 2) {
            return Arrays.asList(min, max);
        }
        List<Integer> values;
        if (num > (max - min)) {
            values = new ArrayList<>(max - min + 1);
            for (int i = min; i <= max; i++) {
                values.add(i);
            }
        } else {
            values = new ArrayList<>(num);
            double diff = (max - min) / (num - 1.0);
            values.add(min);
            for (int i = 1; i < num - 1; i++) {
                values.add((int) Math.round(values.get(i - 1) + diff));
            }
            values.add(max);
        }
        return values;
    }

    /**
     * @param rdg random number generator to use
     * @return a hyperparameter value chosen uniformly at random from the range
     */
    @Override
    public Integer getRandomValue(RandomDataGenerator rdg) {
        if (max == min) {
            return min;
        }
        return rdg.nextInt(min, max);
    }

    /**
     * @return max - min + 1
     */
    @Override
    public long getNumDistinctValues() {
        return (long) max - min + 1;
    }

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

}