cc.kave.commons.pointsto.evaluation.cv.ProjectCVFoldBuilder.java Source code

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Here is the source code for cc.kave.commons.pointsto.evaluation.cv.ProjectCVFoldBuilder.java

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/**
 * Copyright 2016 Simon Reu
 *
 * 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 cc.kave.commons.pointsto.evaluation.cv;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;

import org.apache.commons.math3.random.RandomGenerator;

import com.google.inject.Inject;

import cc.kave.commons.pointsto.evaluation.annotations.NumberOfCVFolds;
import cc.kave.commons.pointsto.stores.ProjectIdentifier;
import cc.recommenders.usages.Usage;

public class ProjectCVFoldBuilder extends AbstractCVFoldBuilder {

    @Inject
    public ProjectCVFoldBuilder(@NumberOfCVFolds int numFolds, RandomGenerator rndGenerator) {
        super(numFolds, rndGenerator);
    }

    @Override
    public List<List<Usage>> createFolds(Map<ProjectIdentifier, List<Usage>> projectUsages) {
        List<ProjectIdentifier> projects = new ArrayList<>(projectUsages.keySet());
        // sort projects in ascending order according to the number of usages
        projects.sort(new Comparator<ProjectIdentifier>() {

            @Override
            public int compare(ProjectIdentifier o1, ProjectIdentifier o2) {
                return projectUsages.get(o1).size() - projectUsages.get(o2).size();
            }
        });

        List<List<Usage>> folds = createFolds(calcAvgFoldSize(projectUsages.values()));
        for (int i = projects.size() - 1; i >= 0; --i) {
            ProjectIdentifier project = projects.get(i);
            List<Usage> fold = getSmallestFold(folds);

            fold.addAll(projectUsages.remove(project));
        }

        shuffleUsages(folds);
        return folds;
    }

    private List<List<Usage>> createFolds(int avgFoldSize) {
        List<List<Usage>> folds = new ArrayList<>(numFolds);
        for (int i = 0; i < numFolds; ++i) {
            folds.add(new ArrayList<>(avgFoldSize));
        }

        return folds;
    }

    private List<Usage> getSmallestFold(List<List<Usage>> folds) {
        int minFoldSize = Integer.MAX_VALUE;
        List<Usage> smallestFold = Collections.emptyList();

        for (List<Usage> fold : folds) {
            if (fold.size() < minFoldSize) {
                minFoldSize = fold.size();
                smallestFold = fold;
            }
        }

        return smallestFold;
    }

}