package edu.brown.mappings;
import java.util.Random;
import edu.brown.mappings.PearsonCorrelationMapping;
import junit.framework.TestCase;
public class TestPearsonCorrelationMapping extends TestCase {
private final Random rand = new Random(0);
private final int num_samples = 1000;
public static double roundToDecimals(double d, int c) {
return (Double.parseDouble(String.format("%." + c + "g", d)));
}
/**
* testNoSamples
*/
public void testNoSamples() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
assertNull(p.calculate());
}
/**
* testClear
*/
public void testClear() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(i, i);
} // FOR
p.clear();
assertEquals(0, p.size());
assertNull(p.calculate());
}
/**
* testSingleSample
*/
public void testSingleSample() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
p.addOccurrence(1, 1);
Double result = p.calculate();
assertNotNull(result);
assertEquals(1.0d, roundToDecimals(result, 1));
}
/**
* testIntegers
*/
public void testIntegers() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(Integer.MAX_VALUE, Integer.MAX_VALUE);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
p.clear();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(Integer.MIN_VALUE, Integer.MIN_VALUE);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
}
/**
* testLongs
*/
public void testLongs() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(Long.MAX_VALUE, Long.MAX_VALUE);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
p.clear();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(Long.MIN_VALUE, Long.MIN_VALUE);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
}
/**
* testDoubles
*/
public void testDoubles() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(Double.MAX_VALUE, Double.MAX_VALUE);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
p.clear();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(Double.MIN_VALUE, Double.MIN_VALUE);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
}
/**
* testAbsolutePositive
*/
public void testAbsolutePositive() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(i, i);
}
assertEquals(1.0d, roundToDecimals(p.calculate(), 1));
}
/**
* testAbsoluteNegative
*/
public void testAbsoluteNegative() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(i, -i);
}
assertEquals(-1.0d, roundToDecimals(p.calculate(), 1));
}
/**
* testRandomCorrelation
*/
public void testRandomCorrelation() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(i, (this.rand.nextDouble() - 0.5) * i);
}
assertTrue(Math.abs(p.calculate()) < 0.1);
}
/**
* testPositiveCorrelation
*/
public void testPositiveCorrelation() {
PearsonCorrelationMapping p = new PearsonCorrelationMapping();
for (int i = 0; i < num_samples; i++) {
p.addOccurrence(i, (this.rand.nextDouble()) * i);
}
assertTrue(Math.abs(p.calculate()) > 0.4);
}
}