Example usage for org.apache.commons.math4.stat.descriptive.moment StandardDeviation StandardDeviation

Introduction

In this page you can find the example usage for org.apache.commons.math4.stat.descriptive.moment StandardDeviation StandardDeviation.

Prototype

public StandardDeviation() 

Source Link

Document

Constructs a StandardDeviation.

Usage

From source file:delfos.group.results.groupevaluationmeasures.MAE_byGroupStdDev.java

@Override
public GroupEvaluationMeasureResult getMeasureResult(GroupRecommenderSystemResult groupRecommenderSystemResult,
        DatasetLoader<? extends Rating> originalDatasetLoader, RelevanceCriteria relevanceCriteria,
        DatasetLoader<? extends Rating> trainingDatasetLoader,
        DatasetLoader<? extends Rating> testDatasetLoader) {

    TreeMap<GroupOfUsers, MeanIterative> maeGroups = new TreeMap<>();

    for (GroupOfUsers groupOfUsers : groupRecommenderSystemResult.getGroupsOfUsers()) {
        Collection<Recommendation> groupRecommendations = groupRecommenderSystemResult
                .getGroupOutput(groupOfUsers).getRecommendations().getRecommendations();

        if (groupRecommendations.isEmpty()) {
            continue;
        }//w w w.  j  a  v  a2s  . c om
        MeanIterative maeGroup = new MeanIterative();

        Map<Integer, Map<Integer, ? extends Rating>> groupTrueRatings = new TreeMap<>();

        groupOfUsers.getIdMembers().stream().forEach((idUser) -> {
            try {
                groupTrueRatings.put(idUser, testDatasetLoader.getRatingsDataset().getUserRatingsRated(idUser));
            } catch (UserNotFound ex) {
                ERROR_CODES.USER_NOT_FOUND.exit(ex);
            }
        });

        for (Recommendation recommendation : groupRecommendations) {
            if (Double.isNaN(recommendation.getPreference().doubleValue())) {
                continue;
            }
            int idItem = recommendation.getItem().getId();
            for (int idUser : groupOfUsers.getIdMembers()) {
                if (groupTrueRatings.get(idUser).containsKey(idItem)) {
                    double trueRating = groupTrueRatings.get(idUser).get(idItem).getRatingValue().doubleValue();
                    double predicted = recommendation.getPreference().doubleValue();
                    double absoluteError = Math.abs(predicted - trueRating);

                    maeGroup.addValue(absoluteError);
                }
            }
        }

        maeGroups.put(groupOfUsers, maeGroup);

    }

    double[] maesByGroup = maeGroups.values().parallelStream().mapToDouble(maeGroup -> maeGroup.getMean())
            .filter(value -> !Double.isNaN(value)).toArray();

    double maeByGroupStdDev = new StandardDeviation().evaluate(maesByGroup);

    if (maesByGroup.length == 0) {
        return new GroupEvaluationMeasureResult(this, Double.NaN);
    } else {
        return new GroupEvaluationMeasureResult(this, maeByGroupStdDev);
    }
}

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From source file:delfos.group.results.groupevaluationmeasures.MAE_byMemberStdDev.java

@Override
public GroupEvaluationMeasureResult getMeasureResult(GroupRecommenderSystemResult groupRecommenderSystemResult,
        DatasetLoader<? extends Rating> originalDatasetLoader, RelevanceCriteria relevanceCriteria,
        DatasetLoader<? extends Rating> trainingDatasetLoader,
        DatasetLoader<? extends Rating> testDatasetLoader) {

    TreeMap<Integer, MeanIterative> maeAllMembers = new TreeMap<>();

    for (GroupOfUsers groupOfUsers : groupRecommenderSystemResult.getGroupsOfUsers()) {
        Collection<Recommendation> groupRecommendations = groupRecommenderSystemResult
                .getGroupOutput(groupOfUsers).getRecommendations().getRecommendations();

        if (groupRecommendations.isEmpty()) {
            continue;
        }//from w  w w. ja  va  2  s  .  c o  m
        MeanIterative maeGroup = new MeanIterative();
        Map<Integer, MeanIterative> maeMembers = new TreeMap<>();
        for (User member : groupOfUsers.getMembers()) {
            maeMembers.put(member.getId(), new MeanIterative());
        }

        Map<Integer, Map<Integer, ? extends Rating>> groupTrueRatings = new TreeMap<>();

        groupOfUsers.getIdMembers().stream().forEach((idUser) -> {
            try {
                groupTrueRatings.put(idUser, testDatasetLoader.getRatingsDataset().getUserRatingsRated(idUser));
            } catch (UserNotFound ex) {
                ERROR_CODES.USER_NOT_FOUND.exit(ex);
            }
        });

        for (Recommendation recommendation : groupRecommendations) {
            if (Double.isNaN(recommendation.getPreference().doubleValue())) {
                continue;
            }
            int idItem = recommendation.getItem().getId();
            for (int idUser : groupOfUsers.getIdMembers()) {
                if (groupTrueRatings.get(idUser).containsKey(idItem)) {
                    double trueRating = groupTrueRatings.get(idUser).get(idItem).getRatingValue().doubleValue();
                    double predicted = recommendation.getPreference().doubleValue();
                    double absoluteError = Math.abs(predicted - trueRating);

                    maeGroup.addValue(absoluteError);
                    maeMembers.get(idUser).addValue(absoluteError);
                }
            }
        }

        maeAllMembers.putAll(maeMembers);

    }

    double[] maeByMember = maeAllMembers.values().parallelStream()
            .mapToDouble(meanMember -> meanMember.getMean()).filter(value -> !Double.isNaN(value)).toArray();

    double maeByMemberStdDev = new StandardDeviation().evaluate(maeByMember);

    if (maeByMember.length == 0) {
        return new GroupEvaluationMeasureResult(this, Double.NaN);
    } else {
        return new GroupEvaluationMeasureResult(this, maeByMemberStdDev);
    }
}

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