// Path: core/src/java/main/org/uncommons/maths/random/ExponentialGenerator.java
// public class ExponentialGenerator implements NumberGenerator<Double>
// {
//     private final NumberGenerator<Double> rate;
//     private final Random rng;
// 
// 
//     /**
//      * Creates a generator of exponentially-distributed values from a distribution
//      * with a rate controlled by the specified generator parameter.  The mean of
//      * this distribution is {@literal 1 / rate}
//      * and the variance is {@literal 1 / rate^2}.
//      * @param rate A number generator that provides values to use as the rate for
//      * the exponential distribution.  This generator must only return non-zero, positive
//      * values.
//      * @param rng The source of randomness used to generate the exponential values.
//      */
//     public ExponentialGenerator(NumberGenerator<Double> rate,
//                                 Random rng)
//     {
//         this.rate = rate;
//         this.rng = rng;
//     }
// 
// 
//     /**
//      * Creates a generator of exponentially-distributed values from a distribution
//      * with the specified rate.  The mean of this distribution is {@literal 1 / rate}
//      * and the variance is {@literal 1 / rate^2}.
//      * @param rate The rate (lamda) of the exponential distribution.
//      * @param rng The source of randomness used to generate the exponential values.
//      */
//     public ExponentialGenerator(double rate,
//                                 Random rng)
//     {
//         this(new ConstantGenerator<Double>(rate), rng);
//     }
// 
// 
//     /**
//      * Generate the next exponential value from the current value of
//      * {@literal rate}.
//      * @return The next exponentially-distributed value.
//      */
//     public Double nextValue()
//     {
//         double u;
//         do
//         {
//             // Get a uniformly-distributed random double between
//             // zero (inclusive) and 1 (exclusive)
//             u = rng.nextDouble();
//         } while (u == 0d); // Reject zero, u must be positive for this to work.
//         return (-Math.log(u)) / rate.nextValue();
//     }
// }


import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import org.uncommons.maths.random.ExponentialGenerator;
// ============================================================================
//   Copyright 2006-2012 Daniel W. Dyer
//
//   Licensed 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.uncommons.maths.demo;


/**
 * @author Daniel Dyer
 */
class ExponentialDistribution extends ProbabilityDistribution
{
    private final double rate;


    public ExponentialDistribution(double rate)
    {
        this.rate = rate;
    }


// Path: core/src/java/main/org/uncommons/maths/random/ExponentialGenerator.java
// public class ExponentialGenerator implements NumberGenerator<Double>
// {
//     private final NumberGenerator<Double> rate;
//     private final Random rng;
// 
// 
//     /**
//      * Creates a generator of exponentially-distributed values from a distribution
//      * with a rate controlled by the specified generator parameter.  The mean of
//      * this distribution is {@literal 1 / rate}
//      * and the variance is {@literal 1 / rate^2}.
//      * @param rate A number generator that provides values to use as the rate for
//      * the exponential distribution.  This generator must only return non-zero, positive
//      * values.
//      * @param rng The source of randomness used to generate the exponential values.
//      */
//     public ExponentialGenerator(NumberGenerator<Double> rate,
//                                 Random rng)
//     {
//         this.rate = rate;
//         this.rng = rng;
//     }
// 
// 
//     /**
//      * Creates a generator of exponentially-distributed values from a distribution
//      * with the specified rate.  The mean of this distribution is {@literal 1 / rate}
//      * and the variance is {@literal 1 / rate^2}.
//      * @param rate The rate (lamda) of the exponential distribution.
//      * @param rng The source of randomness used to generate the exponential values.
//      */
//     public ExponentialGenerator(double rate,
//                                 Random rng)
//     {
//         this(new ConstantGenerator<Double>(rate), rng);
//     }
// 
// 
//     /**
//      * Generate the next exponential value from the current value of
//      * {@literal rate}.
//      * @return The next exponentially-distributed value.
//      */
//     public Double nextValue()
//     {
//         double u;
//         do
//         {
//             // Get a uniformly-distributed random double between
//             // zero (inclusive) and 1 (exclusive)
//             u = rng.nextDouble();
//         } while (u == 0d); // Reject zero, u must be positive for this to work.
//         return (-Math.log(u)) / rate.nextValue();
//     }
// }


// Path: demo/src/java/main/org/uncommons/maths/demo/ExponentialDistribution.java
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import org.uncommons.maths.random.ExponentialGenerator;

// ============================================================================
//   Copyright 2006-2012 Daniel W. Dyer
//
//   Licensed 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.uncommons.maths.demo;


/**
 * @author Daniel Dyer
 */
class ExponentialDistribution extends ProbabilityDistribution
{
    private final double rate;


    public ExponentialDistribution(double rate)
    {
        this.rate = rate;
    }


    protected ExponentialGenerator createValueGenerator(Random rng)