org.apache.solr.client.solrj.io.eval.MannWhitneyUEvaluator.java Source code

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Here is the source code for org.apache.solr.client.solrj.io.eval.MannWhitneyUEvaluator.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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
 *
 * 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 org.apache.solr.client.solrj.io.eval;

import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.stream.Collectors;

import org.apache.commons.math3.stat.inference.MannWhitneyUTest;
import org.apache.solr.client.solrj.io.Tuple;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;

public class MannWhitneyUEvaluator extends RecursiveNumericListEvaluator implements ManyValueWorker {
    protected static final long serialVersionUID = 1L;

    public MannWhitneyUEvaluator(StreamExpression expression, StreamFactory factory) throws IOException {
        super(expression, factory);

        if (containedEvaluators.size() < 1) {
            throw new IOException(
                    String.format(Locale.ROOT, "Invalid expression %s - expecting at least one value but found %d",
                            expression, containedEvaluators.size()));
        }
    }

    @Override
    public Object doWork(Object... values) throws IOException {
        List<double[]> mannWhitneyUInput = Arrays.stream(values)
                .map(value -> ((List<Number>) value).stream().mapToDouble(Number::doubleValue).toArray())
                .collect(Collectors.toList());
        if (mannWhitneyUInput.size() == 2) {
            MannWhitneyUTest mannwhitneyutest = new MannWhitneyUTest();
            double u = mannwhitneyutest.mannWhitneyU(mannWhitneyUInput.get(0), mannWhitneyUInput.get(1));
            double p = mannwhitneyutest.mannWhitneyUTest(mannWhitneyUInput.get(0), mannWhitneyUInput.get(1));
            Map<String, Number> m = new HashMap<>();
            m.put("u-statistic", u);
            m.put("p-value", p);
            return new Tuple(m);
        } else {
            throw new IOException(String.format(Locale.ROOT,
                    "%s(...) only works with a list of 2 arrays but a list of %d array(s) was provided.",
                    constructingFactory.getFunctionName(getClass()), mannWhitneyUInput.size()));
        }
    }
}