/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2014, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* --------------------
* StatisticsTests.java
* --------------------
* (C) Copyright 2004-2014, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 25-Mar-2004 : Version 1 (DG);
* 04-Oct-2004 : Eliminated NumberUtils usage (DG);
*
*/
package org.jfree.data.statistics;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
/**
* Tests for the {@link Statistics} class.
*/
public class StatisticsTest {
/**
* Some checks for the calculateMean(Number[]) and
* calculateMean(Number[], boolean) methods.
*/
@Test
public void testCalculateMean_Array() {
// try null array
try {
Statistics.calculateMean((Number[]) null);
fail("IllegalArgumentException should have been thrown on null key");
}
catch (IllegalArgumentException e) {
assertEquals("Null 'values' argument.", e.getMessage());
}
try {
Statistics.calculateMean((Number[]) null, false);
fail("IllegalArgumentException should have been thrown on negative key");
}
catch (IllegalArgumentException e) {
assertEquals("Null 'values' argument.", e.getMessage());
}
// try an array containing no items
assertTrue(Double.isNaN(Statistics.calculateMean(new Number[0])));
assertTrue(Double.isNaN(Statistics.calculateMean(new Number[0],
false)));
// try an array containing a single Number
Number[] values = new Number[] {1.0};
assertEquals(1.0, Statistics.calculateMean(values), EPSILON);
assertEquals(1.0, Statistics.calculateMean(values, true), EPSILON);
assertEquals(1.0, Statistics.calculateMean(values, false), EPSILON);
// try an array containing a single Number and a null
values = new Number[] {1.0, null};
assertTrue(Double.isNaN(Statistics.calculateMean(values)));
assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
assertEquals(1.0, Statistics.calculateMean(values, false), EPSILON);
// try an array containing a single Number and a NaN
values = new Number[] {1.0, Double.NaN};
assertTrue(Double.isNaN(Statistics.calculateMean(values)));
assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
assertEquals(1.0, Statistics.calculateMean(values, false), EPSILON);
}
/**
* Some checks for the calculateMean(Collection) and
* calculateMean(Collection, boolean) methods.
*/
@Test
public void testCalculateMean_Collection() {
// try a null collection
try {
Statistics.calculateMean((Collection<Number>) null);
fail("IllegalArgumentException should have been thrown on null key");
}
catch (IllegalArgumentException e) {
assertEquals("Null 'values' argument.", e.getMessage());
}
try {
Statistics.calculateMean((Collection<Number>) null, false);
fail("IllegalArgumentException should have been thrown on null key");
}
catch (IllegalArgumentException e) {
assertEquals("Null 'values' argument.", e.getMessage());
}
// try an empty collection
List<Number> values = new ArrayList<Number>();
assertTrue(Double.isNaN(Statistics.calculateMean(values)));
assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
assertTrue(Double.isNaN(Statistics.calculateMean(values, false)));
// try a collection with a single number
values.add(9.0);
assertEquals(9.0, Statistics.calculateMean(values), EPSILON);
assertEquals(9.0, Statistics.calculateMean(values, true), EPSILON);
assertEquals(9.0, Statistics.calculateMean(values, false), EPSILON);
// try a collection with a single number plus a null
values.add(null);
assertTrue(Double.isNaN(Statistics.calculateMean(values)));
assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
assertEquals(9.0, Statistics.calculateMean(values, false), EPSILON);
// try a collection with a single number plus a NaN
values.clear();
values.add(9.0);
values.add(Double.NaN);
assertTrue(Double.isNaN(Statistics.calculateMean(values)));
assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
assertEquals(9.0, Statistics.calculateMean(values, false), EPSILON);
// try a collection with several numbers
values = new ArrayList<Number>();
values.add(9.0);
values.add(3.0);
values.add(2.0);
values.add(2.0);
double mean = Statistics.calculateMean(values);
assertEquals(4.0, mean, EPSILON);
// a Collection containing a NaN will return Double.NaN for the result
values.add(Double.NaN);
assertTrue(Double.isNaN(Statistics.calculateMean(values)));
}
static final double EPSILON = 0.0000000001;
/**
* Some checks for the calculateMedian(List, boolean) method.
*/
@Test
public void testCalculateMedian() {
// check null list
assertTrue(Double.isNaN(Statistics.calculateMedian(null, false)));
assertTrue(Double.isNaN(Statistics.calculateMedian(null, true)));
// check empty list
List <Number>list = new ArrayList<Number>();
assertTrue(Double.isNaN(Statistics.calculateMedian(list, false)));
assertTrue(Double.isNaN(Statistics.calculateMedian(list, true)));
// check list containing null
list.add(null);
try {
Statistics.calculateMedian(list, false);
fail("Should have thrown a NullPointerException");
}
catch (NullPointerException e) {
//we expect ot go in here
}
try {
Statistics.calculateMedian(list, true);
fail("Should have thrown a NullPointerException");
}
catch (NullPointerException e) {
//we expect to go in here
}
}
/**
* A test for the calculateMedian() method.
*/
@Test
public void testCalculateMedian1() {
List<Number> values = new ArrayList<Number>();
values.add(1.0);
double median = Statistics.calculateMedian(values);
assertEquals(1.0, median, 0.0000001);
}
/**
* A test for the calculateMedian() method.
*/
@Test
public void testCalculateMedian2() {
List<Number> values = new ArrayList<Number>();
values.add(2.0);
values.add(1.0);
double median = Statistics.calculateMedian(values);
assertEquals(1.5, median, 0.0000001);
}
/**
* A test for the calculateMedian() method.
*/
@Test
public void testCalculateMedian3() {
List<Number> values = new ArrayList<Number>();
values.add(1.0);
values.add(2.0);
values.add(3.0);
values.add(6.0);
values.add(5.0);
values.add(4.0);
double median = Statistics.calculateMedian(values);
assertEquals(3.5, median, 0.0000001);
}
/**
* A test for the calculateMedian() method.
*/
@Test
public void testCalculateMedian4() {
List<Number> values = new ArrayList<Number>();
values.add(7.0);
values.add(2.0);
values.add(3.0);
values.add(5.0);
values.add(4.0);
values.add(6.0);
values.add(1.0);
double median = Statistics.calculateMedian(values);
assertEquals(4.0, median, 0.0000001);
}
/**
* A test using some real data that caused a problem at one point.
*/
@Test
public void testCalculateMedian5() {
List<Number> values = new ArrayList<Number>();
values.add(11.228692993861783);
values.add(11.30823353859889);
values.add(11.75312904769314);
values.add(11.825102897465314);
values.add(10.184252778401783);
values.add(12.207951828057766);
values.add(10.68841994040566);
values.add(12.099522004479438);
values.add(11.508874945056881);
values.add(12.052517729558513);
values.add(12.401481645578734);
values.add(12.185377793028543);
values.add(10.666372951930315);
values.add(11.680978041499548);
values.add(11.06528277406718);
values.add(11.36876492904596);
values.add(11.927565516175939);
values.add(11.39307785978655);
values.add(11.989603679523857);
values.add(12.009834360354864);
values.add(10.653351822461559);
values.add(11.851776254376754);
values.add(11.045441544755946);
values.add(11.993674040560624);
values.add(12.898219965238944);
values.add(11.97095782819647);
values.add(11.73234406745488);
values.add(11.649006017243991);
values.add(12.20549704915365);
values.add(11.799723639384919);
values.add(11.896208658005628);
values.add(12.164149111823424);
values.add(12.042795103513766);
values.add(12.114839532596426);
values.add(12.166609097075824);
values.add(12.183017546225935);
values.add(11.622009125845342);
values.add(11.289365786738633);
values.add(12.462984323671568);
values.add(11.573494921030598);
values.add(10.862867940485804);
values.add(12.018186939664872);
values.add(10.418046849313018);
values.add(11.326344465881341);
double median = Statistics.calculateMedian(values, true);
assertEquals(11.812413268425116, median, 0.000001);
Collections.sort((List) values);
double median2 = Statistics.calculateMedian(values, false);
assertEquals(11.812413268425116, median2, 0.000001);
}
/**
* A test for the calculateMedian() method.
*/
@Test
public void testCalculateMedian6() {
List<Number> values = new ArrayList<Number>();
values.add(7.0);
values.add(2.0);
values.add(3.0);
values.add(5.0);
values.add(4.0);
values.add(6.0);
values.add(1.0);
double median = Statistics.calculateMedian(values, 0, 2);
assertEquals(3.0, median, 0.0000001);
}
/**
* A simple test for the correlation calculation.
*/
@Test
public void testCorrelation1() {
Number[] data1 = new Number[3];
data1[0] = (double) 1;
data1[1] = (double) 2;
data1[2] = (double) 3;
Number[] data2 = new Number[3];
data2[0] = (double) 1;
data2[1] = (double) 2;
data2[2] = (double) 3;
double r = Statistics.getCorrelation(data1, data2);
assertEquals(1.0, r, 0.00000001);
}
/**
* A simple test for the correlation calculation.
*
* http://trochim.human.cornell.edu/kb/statcorr.htm
*/
@Test
public void testCorrelation2() {
Number[] data1 = new Number[20];
data1[0] = (double) 68;
data1[1] = (double) 71;
data1[2] = (double) 62;
data1[3] = (double) 75;
data1[4] = (double) 58;
data1[5] = (double) 60;
data1[6] = (double) 67;
data1[7] = (double) 68;
data1[8] = (double) 71;
data1[9] = (double) 69;
data1[10] = (double) 68;
data1[11] = (double) 67;
data1[12] = (double) 63;
data1[13] = (double) 62;
data1[14] = (double) 60;
data1[15] = (double) 63;
data1[16] = (double) 65;
data1[17] = (double) 67;
data1[18] = (double) 63;
data1[19] = (double) 61;
Number[] data2 = new Number[20];
data2[0] = 4.1;
data2[1] = 4.6;
data2[2] = 3.8;
data2[3] = 4.4;
data2[4] = 3.2;
data2[5] = 3.1;
data2[6] = 3.8;
data2[7] = 4.1;
data2[8] = 4.3;
data2[9] = 3.7;
data2[10] = 3.5;
data2[11] = 3.2;
data2[12] = 3.7;
data2[13] = 3.3;
data2[14] = 3.4;
data2[15] = 4.0;
data2[16] = 4.1;
data2[17] = 3.8;
data2[18] = 3.4;
data2[19] = 3.6;
double r = Statistics.getCorrelation(data1, data2);
assertEquals(0.7306356862792885, r, 0.000000000001);
}
/**
* Some checks for the getStdDev() method.
*/
@Test
public void testGetStdDev() {
// try null argument
try {
Statistics.getStdDev(null);
fail("IllegalArgumentException should have been thrown on null key");
}
catch (IllegalArgumentException e) {
assertEquals("Null 'data' argument.", e.getMessage());
}
// try zero length array
try {
Statistics.getStdDev(new Double[0]);
fail("IllegalArgumentException should have been thrown on empty key");
}
catch (IllegalArgumentException e) {
assertEquals("Zero length 'data' array.", e.getMessage());
}
// try single value
assertTrue(Double.isNaN(Statistics.getStdDev(new Double[]
{1.0})));
}
}