com.github.jessemull.microflexbigdecimal.stat.SkewnessTest.java Source code

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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 --------------------------------- */

package com.github.jessemull.microflexbigdecimal.stat;

/* ------------------------------ Dependencies ------------------------------ */

import static org.junit.Assert.*;

import java.io.OutputStream;
import java.io.PrintStream;
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.TreeMap;
import java.util.Map;
import java.util.Random;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runners.MethodSorters;

import com.github.jessemull.microflexbigdecimal.plate.Plate;
import com.github.jessemull.microflexbigdecimal.plate.Well;
import com.github.jessemull.microflexbigdecimal.plate.WellSet;
import com.github.jessemull.microflexbigdecimal.stat.Skewness;
import com.github.jessemull.microflexbigdecimal.util.RandomUtil;

/**
 * This class tests the methods in the skewness big decimal class.
 * 
 * @author Jesse L. Mull
 * @update Updated Oct 18, 2016
 * @address http://www.jessemull.com
 * @email hello@jessemull.com
 */
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class SkewnessTest {

    /* ---------------------------- Local Fields -----------------------------*/

    /* Minimum and maximum values for random well and lists */

    private static BigDecimal minValue = new BigDecimal(0); // Minimum big decimal value for wells
    private static BigDecimal maxValue = new BigDecimal(10); // Maximum big decimal value for wells
    private static Random random = new Random(); // Generates random integers
    private static MathContext mc = new MathContext(10, RoundingMode.HALF_DOWN); // Math context for input values

    /* The addition operation */

    private static Skewness skewness = new Skewness();

    /* Random objects and numbers for testing */

    private static int rows = 5;
    private static int columns = 4;
    private static int length = 5;
    private static int lengthIndices = 10;
    private static int plateNumber = 10;
    private static int plateNumberIndices = 5;
    private static Plate[] array = new Plate[plateNumber];
    private static Plate[] arrayIndices = new Plate[plateNumberIndices];

    /* Value of false redirects System.err */

    private static boolean error = true;
    private static PrintStream originalOut = System.out;

    /**
     * Generates random objects and numbers for testing.
     */
    @BeforeClass
    public static void setUp() {

        if (error) {

            System.setErr(new PrintStream(new OutputStream() {
                public void write(int x) {
                }
            }));

        }

        for (int j = 0; j < array.length; j++) {

            Plate plate = RandomUtil.randomPlateBigDecimal(rows, columns, minValue, maxValue, length,
                    "Plate1-" + j);

            array[j] = plate;
        }

        for (int j = 0; j < arrayIndices.length; j++) {

            Plate plateIndices = RandomUtil.randomPlateBigDecimal(rows, columns, minValue, maxValue, lengthIndices,
                    "Plate1-" + j);

            arrayIndices[j] = plateIndices;
        }
    }

    /**
     * Toggles system error.
     */
    @AfterClass
    public static void restoreErrorOut() {
        System.setErr(originalOut);
    }

    /* ---------------------------- Constructors -----------------------------*/

    /**
     * Tests the default constructor.
     */
    @Test
    public void testConstructor() {
        Skewness test = new Skewness();
        assertNotNull(test);
    }

    /* ---------------- Well statistics for all plate wells ----------------- */

    /**
     * Tests the plate statistics method.
     */
    @Test
    public void testPlate() {

        for (Plate plate : array) {

            Map<Well, BigDecimal> resultMap = new TreeMap<Well, BigDecimal>();
            Map<Well, BigDecimal> returnedMap = skewness.plate(plate, mc);

            for (Well well : plate) {

                double[] input = new double[well.size()];
                int index = 0;

                for (BigDecimal bd : well) {
                    input[index++] = bd.doubleValue();
                }

                DescriptiveStatistics stat = new DescriptiveStatistics(input);
                double resultDouble = stat.getSkewness();

                BigDecimal result = new BigDecimal(resultDouble);

                resultMap.put(well, result);
            }

            for (Well well : plate) {

                BigDecimal result = resultMap.get(well);
                BigDecimal returned = returnedMap.get(well);

                BigDecimal[] corrected = correctRoundingErrors(result, returned);

                assertEquals(corrected[0], corrected[1]);
            }
        }
    }

    /**
     * Tests the plate statistics method using the values between the indices.
     */
    @Test
    public void testPlateIndices() {

        for (Plate plate : arrayIndices) {

            int size = arrayIndices[0].first().size();
            int begin = random.nextInt(size - 5);
            int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

            Map<Well, BigDecimal> resultMap = new TreeMap<Well, BigDecimal>();
            Map<Well, BigDecimal> returnedMap = skewness.plate(plate, begin, end - begin, mc);

            for (Well well : plate) {

                double[] input = new double[well.size()];
                int index = 0;

                for (BigDecimal bd : well) {
                    input[index++] = bd.doubleValue();
                }

                DescriptiveStatistics stat = new DescriptiveStatistics(ArrayUtils.subarray(input, begin, end));
                double resultDouble = stat.getSkewness();

                BigDecimal result = new BigDecimal(resultDouble);

                resultMap.put(well, result);
            }

            for (Well well : plate) {

                BigDecimal result = resultMap.get(well);
                BigDecimal returned = returnedMap.get(well);

                BigDecimal[] corrected = correctRoundingErrors(result, returned);

                assertEquals(corrected[0], corrected[1]);
            }
        }
    }

    /* --------------------- Aggregated plate statistics -------------------  */

    /**
     * Tests the aggregated plate statistics method.
     */
    @Test
    public void testAggregatedPlate() {

        for (Plate plate : array) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();
            BigDecimal aggregatedReturned = skewness.platesAggregated(plate, mc);

            for (Well well : plate) {
                resultList.addAll(well.data());
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);

            BigDecimal[] corrected = correctRoundingErrors(aggregatedResult, aggregatedReturned);
            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using a collection.
     */
    @Test
    public void testAggregatedPlateCollection() {

        List<Plate> collection = Arrays.asList(array);
        Map<Plate, BigDecimal> aggregatedReturnedMap = skewness.platesAggregated(collection, mc);
        Map<Plate, BigDecimal> aggregatedResultMap = new TreeMap<Plate, BigDecimal>();

        for (Plate plate : collection) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : plate) {
                resultList.addAll(well.data());
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);
            aggregatedResultMap.put(plate, aggregatedResult);
        }

        for (Plate plate : collection) {

            BigDecimal result = aggregatedResultMap.get(plate);
            BigDecimal returned = aggregatedReturnedMap.get(plate);

            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using an array.
     */
    @Test
    public void testAggregatedPlateArray() {

        Map<Plate, BigDecimal> aggregatedReturnedMap = skewness.platesAggregated(array, mc);
        Map<Plate, BigDecimal> aggregatedResultMap = new TreeMap<Plate, BigDecimal>();

        for (Plate plate : array) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : plate) {
                resultList.addAll(well.data());
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);
            aggregatedResultMap.put(plate, aggregatedResult);
        }

        for (Plate plate : array) {

            BigDecimal result = aggregatedResultMap.get(plate);
            BigDecimal returned = aggregatedReturnedMap.get(plate);

            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }

    }

    /**
     * Tests the aggregated plate statistics method using the values between the indices.
     */
    @Test
    public void testAggregatedPlateIndices() {

        for (Plate plate : arrayIndices) {

            int size = arrayIndices[0].first().size();
            int begin = random.nextInt(size - 5);
            int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();
            BigDecimal aggregatedReturned = skewness.platesAggregated(plate, begin, end - begin, mc);

            for (Well well : plate) {
                resultList.addAll(well.data().subList(begin, end));
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);

            BigDecimal[] corrected = correctRoundingErrors(aggregatedResult, aggregatedReturned);
            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using the values between the indices of
     * the collection.
     */
    @Test
    public void testAggregatedPlateCollectionIndices() {

        int size = arrayIndices[0].first().size();
        int begin = random.nextInt(size - 5);
        int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

        List<Plate> collection = Arrays.asList(arrayIndices);
        Map<Plate, BigDecimal> aggregatedReturnedMap = skewness.platesAggregated(collection, begin, end - begin,
                mc);

        Map<Plate, BigDecimal> aggregatedResultMap = new TreeMap<Plate, BigDecimal>();

        for (Plate plate : collection) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : plate) {
                resultList.addAll(well.data().subList(begin, end));
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);
            aggregatedResultMap.put(plate, aggregatedResult);
        }

        for (Plate plate : collection) {

            BigDecimal result = aggregatedResultMap.get(plate);
            BigDecimal returned = aggregatedReturnedMap.get(plate);
            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using the values between the indices of
     * the array.
     */
    @Test
    public void testAggregatedPlateArrayIndices() {

        int size = arrayIndices[0].first().size();
        int begin = random.nextInt(size - 5);
        int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

        Map<Plate, BigDecimal> aggregatedReturnedMap = skewness.platesAggregated(arrayIndices, begin, end - begin,
                mc);
        Map<Plate, BigDecimal> aggregatedResultMap = new TreeMap<Plate, BigDecimal>();

        for (Plate plate : arrayIndices) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : plate) {
                resultList.addAll(well.data().subList(begin, end));
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);

            aggregatedResultMap.put(plate, aggregatedResult);
        }

        for (Plate plate : arrayIndices) {

            BigDecimal result = aggregatedResultMap.get(plate);
            BigDecimal returned = aggregatedReturnedMap.get(plate);
            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }
    }

    /* --------------- Well statistics for all wells in a set --------------  */

    /**
     * Tests set calculation.
     */
    @Test
    public void testSet() {

        for (Plate plate : array) {

            Map<Well, BigDecimal> resultMap = new TreeMap<Well, BigDecimal>();
            Map<Well, BigDecimal> returnedMap = skewness.set(plate.dataSet(), mc);

            for (Well well : plate) {

                double[] input = new double[well.size()];
                int index = 0;

                for (BigDecimal bd : well) {
                    input[index++] = bd.doubleValue();
                }

                DescriptiveStatistics stat = new DescriptiveStatistics(input);
                double resultDouble = stat.getSkewness();

                BigDecimal result = new BigDecimal(resultDouble);

                resultMap.put(well, result);
            }

            for (Well well : plate) {

                BigDecimal result = resultMap.get(well);
                BigDecimal returned = returnedMap.get(well);

                BigDecimal[] corrected = correctRoundingErrors(result, returned);

                assertEquals(corrected[0], corrected[1]);
            }
        }

    }

    /**
     * Tests set calculation using indices.
     */
    @Test
    public void testSetIndices() {

        for (Plate plate : arrayIndices) {

            int size = arrayIndices[0].first().size();
            int begin = random.nextInt(size - 5);
            int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

            Map<Well, BigDecimal> resultMap = new TreeMap<Well, BigDecimal>();
            Map<Well, BigDecimal> returnedMap = skewness.set(plate.dataSet(), begin, end - begin, mc);

            for (Well well : plate) {

                double[] input = new double[well.size()];
                int index = 0;

                for (BigDecimal bd : well) {
                    input[index++] = bd.doubleValue();
                }

                DescriptiveStatistics stat = new DescriptiveStatistics(ArrayUtils.subarray(input, begin, end));
                double resultDouble = stat.getSkewness();

                BigDecimal result = new BigDecimal(resultDouble);

                resultMap.put(well, result);
            }

            for (Well well : plate) {

                BigDecimal result = resultMap.get(well);
                BigDecimal returned = returnedMap.get(well);

                BigDecimal[] corrected = correctRoundingErrors(result, returned);

                assertEquals(corrected[0], corrected[1]);
            }
        }
    }

    /* ---------------------- Aggregated set statistics --------------------  */

    /**
     * Tests the aggregated plate statistics method.
     */
    @Test
    public void testAggregatedSet() {

        for (Plate plate : array) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();
            BigDecimal aggregatedReturned = skewness.setsAggregated(plate.dataSet(), mc);

            for (Well well : plate) {
                resultList.addAll(well.data());
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);

            BigDecimal[] corrected = correctRoundingErrors(aggregatedResult, aggregatedReturned);
            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using a collection.
     */
    @Test
    public void testAggregatedSetCollection() {

        List<WellSet> collection = new ArrayList<WellSet>();

        for (Plate plate : array) {
            collection.add(plate.dataSet());
        }

        Map<WellSet, BigDecimal> aggregatedReturnedMap = skewness.setsAggregated(collection, mc);
        Map<WellSet, BigDecimal> aggregatedResultMap = new TreeMap<WellSet, BigDecimal>();

        for (WellSet set : collection) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : set) {
                resultList.addAll(well.data());
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);
            aggregatedResultMap.put(set, aggregatedResult);
        }

        for (WellSet set : collection) {

            BigDecimal result = aggregatedResultMap.get(set);
            BigDecimal returned = aggregatedReturnedMap.get(set);

            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using an array.
     */
    @Test
    public void testAggregatedSetArray() {

        WellSet[] setArray = new WellSet[array.length];

        for (int i = 0; i < setArray.length; i++) {
            setArray[i] = array[i].dataSet();
        }

        Map<WellSet, BigDecimal> aggregatedReturnedMap = skewness.setsAggregated(setArray, mc);
        Map<WellSet, BigDecimal> aggregatedResultMap = new TreeMap<WellSet, BigDecimal>();

        for (WellSet set : setArray) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : set) {
                resultList.addAll(well.data());
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);
            aggregatedResultMap.put(set, aggregatedResult);
        }

        for (WellSet set : setArray) {

            BigDecimal result = aggregatedResultMap.get(set);
            BigDecimal returned = aggregatedReturnedMap.get(set);

            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }

    }

    /**
     * Tests the aggregated plate statistics method using the values between the indices.
     */
    @Test
    public void testAggregatedSetIndices() {

        for (Plate plate : arrayIndices) {

            int size = arrayIndices[0].first().size();
            int begin = random.nextInt(size - 5);
            int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();
            BigDecimal aggregatedReturned = skewness.setsAggregated(plate.dataSet(), begin, end - begin, mc);

            for (Well well : plate) {
                resultList.addAll(well.data().subList(begin, end));
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);

            BigDecimal[] corrected = correctRoundingErrors(aggregatedResult, aggregatedReturned);
            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using the values between the indices of
     * the collection.
     */
    @Test
    public void testAggregatedSetCollectionIndices() {

        int size = arrayIndices[0].first().size();
        int begin = random.nextInt(size - 5);
        int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

        List<WellSet> collection = new ArrayList<WellSet>();

        for (Plate plate : arrayIndices) {
            collection.add(plate.dataSet());
        }

        Map<WellSet, BigDecimal> aggregatedReturnedMap = skewness.setsAggregated(collection, begin, end - begin,
                mc);
        Map<WellSet, BigDecimal> aggregatedResultMap = new TreeMap<WellSet, BigDecimal>();

        for (WellSet set : collection) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : set) {
                resultList.addAll(well.data().subList(begin, end));
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);
            aggregatedResultMap.put(set, aggregatedResult);
        }

        for (WellSet set : collection) {

            BigDecimal result = aggregatedResultMap.get(set);
            BigDecimal returned = aggregatedReturnedMap.get(set);
            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }
    }

    /**
     * Tests the aggregated plate statistics method using the values between the indices of
     * the array.
     */
    @Test
    public void testAggregatedSetArrayIndices() {

        int size = arrayIndices[0].first().size();
        int begin = random.nextInt(size - 5);
        int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

        WellSet[] setArrayIndices = new WellSet[arrayIndices.length];

        for (int i = 0; i < setArrayIndices.length; i++) {
            setArrayIndices[i] = arrayIndices[i].dataSet();
        }

        Map<WellSet, BigDecimal> aggregatedReturnedMap = skewness.setsAggregated(setArrayIndices, begin,
                end - begin, mc);
        Map<WellSet, BigDecimal> aggregatedResultMap = new TreeMap<WellSet, BigDecimal>();

        for (WellSet set : setArrayIndices) {

            List<BigDecimal> resultList = new ArrayList<BigDecimal>();

            for (Well well : set) {
                resultList.addAll(well.data().subList(begin, end));
            }

            double[] inputAggregated = new double[resultList.size()];

            for (int i = 0; i < resultList.size(); i++) {
                inputAggregated[i] = resultList.get(i).doubleValue();
            }

            DescriptiveStatistics statAggregated = new DescriptiveStatistics(inputAggregated);
            double resultAggregatedDouble = statAggregated.getSkewness();

            BigDecimal aggregatedResult = new BigDecimal(resultAggregatedDouble);

            aggregatedResultMap.put(set, aggregatedResult);
        }

        for (WellSet plate : setArrayIndices) {

            BigDecimal result = aggregatedResultMap.get(plate);
            BigDecimal returned = aggregatedReturnedMap.get(plate);
            BigDecimal[] corrected = correctRoundingErrors(result, returned);

            assertEquals(corrected[0], corrected[1]);
        }
    }

    /* -------------------------- Well statistics --------------------------  */

    /**
     * Tests well calculation.
     */
    @Test
    public void testWell() {

        for (Plate plate : array) {

            for (Well well : plate) {

                double[] input = new double[well.size()];
                int index = 0;

                for (BigDecimal bd : well) {
                    input[index++] = bd.doubleValue();
                }

                DescriptiveStatistics stat = new DescriptiveStatistics(input);
                double resultDouble = stat.getSkewness();

                BigDecimal returned = skewness.well(well, mc);
                BigDecimal result = new BigDecimal(resultDouble);

                BigDecimal[] corrected = correctRoundingErrors(returned, result);

                assertEquals(corrected[0], corrected[1]);
            }
        }
    }

    /**
     * Tests well calculation using indices.
     */
    @Test
    public void testWellIndices() {

        for (Plate plate : arrayIndices) {

            for (Well well : plate) {

                double[] input = new double[well.size()];
                int index = 0;

                for (BigDecimal bd : well) {
                    input[index++] = bd.doubleValue();
                }

                int size = arrayIndices[0].first().size();
                int begin = random.nextInt(size - 5);
                int end = (begin + 4) + random.nextInt(size - (begin + 4) + 1);

                DescriptiveStatistics stat = new DescriptiveStatistics(ArrayUtils.subarray(input, begin, end));
                double resultDouble = stat.getSkewness();

                BigDecimal returned = skewness.well(well, begin, end - begin, mc);
                BigDecimal result = new BigDecimal(resultDouble);

                BigDecimal[] corrected = correctRoundingErrors(returned, result);
                assertEquals(corrected[0], corrected[1]);
            }
        }
    }

    /*---------------------------- Helper Methods ----------------------------*/

    /**
     * Corrects any rounding errors due to differences in the implementation of
     * the statistic between the Apache and MicroFlex libraries
     * @param    BigDecimal    the first result
     * @param    BigDecimal    the second result
     * @return                 corrected results
     */
    private static BigDecimal[] correctRoundingErrors(BigDecimal bd1, BigDecimal bd2) {

        BigDecimal[] array = new BigDecimal[2];
        int scale = mc.getPrecision();

        while (!bd1.equals(bd2) && scale > mc.getPrecision() / 4) {

            bd1 = bd1.setScale(scale, RoundingMode.HALF_DOWN);
            bd2 = bd2.setScale(scale, RoundingMode.HALF_DOWN);

            if (bd1.subtract(bd1.ulp()).equals(bd2)) {
                bd1 = bd1.subtract(bd1.ulp());
            }

            if (bd1.add(bd1.ulp()).equals(bd2)) {
                bd1 = bd1.add(bd1.ulp());
            }

            scale--;
        }

        array[0] = bd1;
        array[1] = bd2;

        return array;
    }
}