CIRTemporalPDF.java

package org.drip.sample.kolmogorov;

import org.drip.dynamics.ito.TimeR1Vertex;
import org.drip.dynamics.meanreverting.R1CIRStochasticEvolver;
import org.drip.dynamics.process.R1ProbabilityDensityFunction;
import org.drip.numerical.common.FormatUtil;
import org.drip.service.env.EnvManager;

/*
 * -*- mode: java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 */

/*!
 * Copyright (C) 2020 Lakshmi Krishnamurthy
 * Copyright (C) 2019 Lakshmi Krishnamurthy
 * 
 *  This file is part of DROP, an open-source library targeting risk, transaction costs, exposure, margin
 *  	calculations, valuation adjustment, and portfolio construction within and across fixed income,
 *  	credit, commodity, equity, FX, and structured products.
 *  
 *  	https://lakshmidrip.github.io/DROP/
 *  
 *  DROP is composed of three modules:
 *  
 *  - DROP Analytics Core - https://lakshmidrip.github.io/DROP-Analytics-Core/
 *  - DROP Portfolio Core - https://lakshmidrip.github.io/DROP-Portfolio-Core/
 *  - DROP Numerical Core - https://lakshmidrip.github.io/DROP-Numerical-Core/
 * 
 * 	DROP Analytics Core implements libraries for the following:
 * 	- Fixed Income Analytics
 * 	- Asset Backed Analytics
 * 	- XVA Analytics
 * 	- Exposure and Margin Analytics
 * 
 * 	DROP Portfolio Core implements libraries for the following:
 * 	- Asset Allocation Analytics
 * 	- Transaction Cost Analytics
 * 
 * 	DROP Numerical Core implements libraries for the following:
 * 	- Statistical Learning Library
 * 	- Numerical Optimizer Library
 * 	- Machine Learning Library
 * 	- Spline Builder Library
 * 
 * 	Documentation for DROP is Spread Over:
 * 
 * 	- Main                     => https://lakshmidrip.github.io/DROP/
 * 	- Wiki                     => https://github.com/lakshmiDRIP/DROP/wiki
 * 	- GitHub                   => https://github.com/lakshmiDRIP/DROP
 * 	- Repo Layout Taxonomy     => https://github.com/lakshmiDRIP/DROP/blob/master/Taxonomy.md
 * 	- Javadoc                  => https://lakshmidrip.github.io/DROP/Javadoc/index.html
 * 	- Technical Specifications => https://github.com/lakshmiDRIP/DROP/tree/master/Docs/Internal
 * 	- Release Versions         => https://lakshmidrip.github.io/DROP/version.html
 * 	- Community Credits        => https://lakshmidrip.github.io/DROP/credits.html
 * 	- Issues Catalog           => https://github.com/lakshmiDRIP/DROP/issues
 * 	- JUnit                    => https://lakshmidrip.github.io/DROP/junit/index.html
 * 	- Jacoco                   => https://lakshmidrip.github.io/DROP/jacoco/index.html
 * 
 *  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.
 */

/**
 * <i>CIRTemporalPDF</i> demonstrates the Computation of the PDF from an Evolving R<sup>1</sup>
 * 	Cox-Ingersoll-Ross Process. The References are:
 *  
 * 	<br><br>
 *  <ul>
 * 		<li>
 * 			Bogoliubov, N. N., and D. P. Sankevich (1994): N. N. Bogoliubov and Statistical Mechanics
 * 				<i>Russian Mathematical Surveys</i> <b>49 (5)</b> 19-49
 * 		</li>
 * 		<li>
 * 			Holubec, V., K. Kroy, and S. Steffenoni (2019): Physically Consistent Numerical Solver for
 * 				Time-dependent Fokker-Planck Equations <i>Physical Review E</i> <b>99 (4)</b> 032117
 * 		</li>
 * 		<li>
 * 			Kadanoff, L. P. (2000): <i>Statistical Physics: Statics, Dynamics, and Re-normalization</i>
 * 				<b>World Scientific</b>
 * 		</li>
 * 		<li>
 * 			Ottinger, H. C. (1996): <i>Stochastic Processes in Polymeric Fluids</i> <b>Springer-Verlag</b>
 * 				Berlin-Heidelberg
 * 		</li>
 * 		<li>
 * 			Wikipedia (2019): Fokker-Planck Equation
 * 				https://en.wikipedia.org/wiki/Fokker%E2%80%93Planck_equation
 * 		</li>
 *  </ul>
 *
 *	<br><br>
 *  <ul>
 *		<li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/AnalyticsCore.md">Analytics Core Module</a></li>
 *		<li><b>Library</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/FixedIncomeAnalyticsLibrary.md">Fixed Income Analytics</a></li>
 *		<li><b>Project</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/dynamics/README.md">Dynamics</a></li>
 *		<li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/dynamics/lmm/README.md">LIBOR Market Model</a></li>
 *  </ul>
 *
 * @author Lakshmi Krishnamurthy
 */

public class CIRTemporalPDF
{

	public static final void main (
		final String[] argumentArray)
		throws Exception
	{
		EnvManager.InitEnv (
			""
		);

		double r0 = 3.0;
		double[] timeArray =
		{
			0.5,
			1.0,
			1.5,
			2.0,
			2.5,
			3.0,
			3.5,
			4.0,
			4.5,
			5.0,
			5.5,
			6.0,
			6.5,
			7.0,
			7.5,
			8.0,
			8.5,
			9.0,
			9.5
		};
		double[] xArray =
		{
			 0.01,
			 0.25,
			 0.50,
			 0.75,
			 1.00,
			 1.25,
			 1.50,
			 1.75,
			 2.00,
			 2.25,
			 2.50,
		};
		double[] meanReversionLevelArray =
		{
			 2.0,
			 3.0,
			 4.0,
		};
		double[] meanReversionSpeedArray =
		{
			 0.5,
			 1.0,
			 1.5,
			 2.0,
			 2.5,
		};
		double[] volatilityArray = 
		{
			0.5,
			1.0,
			1.5,
			2.0,
			2.5,
			3.0,
		};

		System.out.println ("\t|------------------------------------------------------------------------------------------------------------------------------------------||");

		System.out.println ("\t|                                                  CIR DISTRIBUTION REALIZATIONS OVER TIME                                                 ||");

		System.out.println ("\t|------------------------------------------------------------------------------------------------------------------------------------------||");

		System.out.println ("\t|        L -> R:                                                                                                                           ||");

		System.out.println ("\t|                - Mean Reversion Speed                                                                                                    ||");

		System.out.println ("\t|                - Mean Reversion Level                                                                                                    ||");

		System.out.println ("\t|                - Volatility                                                                                                              ||");

		System.out.println ("\t|                - Time                                                                                                                    ||");

		System.out.println ("\t|                - Row of PDF Values over x                                                                                                ||");

		System.out.println ("\t|------------------------------------------------------------------------------------------------------------------------------------------||");

		for (double meanReversionSpeed : meanReversionSpeedArray)
		{
			for (double meanReversionLevel : meanReversionLevelArray)
			{
				for (double volatility : volatilityArray)
				{
					R1ProbabilityDensityFunction r1ProbabilityDensityFunction =
						R1CIRStochasticEvolver.Wiener (
							meanReversionSpeed,
							meanReversionLevel,
							volatility,
							0.01
						).fokkerPlanckGenerator().deltaStartTemporalPDF (
							r0
						);

					for (double t : timeArray)
					{
						java.lang.String dump = "\t| [" +
							FormatUtil.FormatDouble (meanReversionSpeed, 1, 1, 1.) + "," +
							FormatUtil.FormatDouble (meanReversionLevel, 1, 1, 1.) + "," +
							FormatUtil.FormatDouble (volatility, 1, 1, 1.) + "]; t =" +
							FormatUtil.FormatDouble (t, 1, 1, 1.) + " =>";

						for (double x : xArray)
						{
							dump = dump + " " + FormatUtil.FormatDouble (
								r1ProbabilityDensityFunction.density (
									new TimeR1Vertex (
										t,
										x
									)
								), 1, 4, 1.
							) + " |";
						}

						System.out.println (dump + "|");
					}

					System.out.println ("\t|------------------------------------------------------------------------------------------------------------------------------------------||");
				}
			}
		}

		System.out.println ("\t|------------------------------------------------------------------------------------------------------------------------------------------||");

		EnvManager.TerminateEnv();
	}
}