src/test/java/org/apache/commons/math3/distribution/LaplaceDistributionTest.java

/*
 * 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.commons.math3.distribution;

import org.apache.commons.math3.util.Precision;
import org.junit.Assert;
import org.junit.Test;

/**
 * Test cases for LaplaceDistribution.
 */
public class LaplaceDistributionTest extends RealDistributionAbstractTest {

    @Test
    public void testParameters() {
        LaplaceDistribution d = makeDistribution();
        Assert.assertEquals(0, d.getLocation(), Precision.EPSILON);
        Assert.assertEquals(1, d.getScale(), Precision.EPSILON);
    }

    @Test
    public void testSupport() {
        LaplaceDistribution d = makeDistribution();
        Assert.assertTrue(Double.isInfinite(d.getSupportLowerBound()));
        Assert.assertTrue(Double.isInfinite(d.getSupportUpperBound()));
        Assert.assertTrue(d.isSupportConnected());
    }

    @Override
    public LaplaceDistribution makeDistribution() {
        return new LaplaceDistribution(0, 1);
    }

    @Override
    public double[] makeCumulativeTestPoints() {
        return new double[] {
            -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5
        };
    }

    @Override
    public double[] makeDensityTestValues() {
        return new double[] {
            0.003368973, 0.009157819, 0.024893534, 0.067667642, 0.183939721,
            0.500000000, 0.183939721, 0.067667642, 0.024893534, 0.009157819, 0.003368973
        };
    }

    @Override
    public double[] makeCumulativeTestValues() {
        return new double[] {
            0.003368973, 0.009157819, 0.024893534, 0.067667642, 0.183939721,
            0.500000000, 0.816060279, 0.932332358, 0.975106466, 0.990842181, 0.996631027
        };
    }

}