com.insightml.data.samples.AbstractSamples.java Source code

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Here is the source code for com.insightml.data.samples.AbstractSamples.java

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/*
 * Copyright (C) 2016 Stefan Hen
 *
 * Licensed 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 com.insightml.data.samples;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

import org.apache.commons.math3.util.Pair;

import com.insightml.data.samples.decorators.FeaturesFilterDecorator;
import com.insightml.data.samples.decorators.SamplesMapping;
import com.insightml.math.Vectors;
import com.insightml.utils.Check;
import com.insightml.utils.types.collections.IntArray;

public abstract class AbstractSamples<S extends Sample, E> implements ISamples<S, E> {

    @Override
    public final SamplesMapping<S, E> subset(final int[] indexes) {
        return new SamplesMapping<>(this, indexes);
    }

    @Override
    public final SamplesMapping<S, E> subset(final int from, final int to) {
        final int[] indexes = new int[to - from];
        for (int i = 0; i < indexes.length; ++i) {
            indexes[i] = i + from;
        }
        return subset(indexes);
    }

    @Override
    public final Pair<ISamples<S, E>, ISamples<S, E>> sample(final double ratio, final Random random) {
        Check.num(ratio, 0.01, 0.95);
        final int n = size();
        if (featureNames() == null) {
            final List<S> list = new LinkedList<>();
            for (int i = 0; i < n; ++i) {
                if (random.nextDouble() <= ratio) {
                    list.add(get(i));
                }
            }
            return new Pair<>(new Samples<>(list), null);
        }
        final IntArray list = new IntArray(n);
        for (int i = 0; i < n; ++i) {
            if (random.nextDouble() <= ratio) {
                list.add(i);
            }
        }
        return new Pair<>(subset(list.toArray()), null);
    }

    @Override
    public final ISamples<S, E> filterFeatures(final boolean[] keep) {
        if (Vectors.sum(keep) == keep.length) {
            return this;
        }
        return new FeaturesFilterDecorator<>(this, keep);
    }

    @Override
    public final ISamples<S, E> sampleFeatures(final double ratio, final Random random) {
        if (ratio >= 1) {
            return this;
        }
        final boolean[] keep = new boolean[numFeatures()];
        for (int i = 0; i < keep.length; ++i) {
            keep[i] = random.nextDouble() <= ratio;
        }
        return filterFeatures(keep);
    }

    @Override
    public Iterator<S> iterator() {
        throw new UnsupportedOperationException();
    }

}