IncompleteEstimate.java

  1. package org.drip.sample.beta;

  2. import org.drip.function.definition.R2ToR1;
  3. import org.drip.function.definition.R3ToR1;
  4. import org.drip.numerical.common.FormatUtil;
  5. import org.drip.service.env.EnvManager;
  6. import org.drip.specialfunction.beta.IncompleteIntegrandEstimator;
  7. import org.drip.specialfunction.beta.IntegrandEstimator;

  8. /*
  9.  * -*- mode: java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  10.  */

  11. /*!
  12.  * Copyright (C) 2020 Lakshmi Krishnamurthy
  13.  * Copyright (C) 2019 Lakshmi Krishnamurthy
  14.  *
  15.  *  This file is part of DROP, an open-source library targeting analytics/risk, transaction cost analytics,
  16.  *      asset liability management analytics, capital, exposure, and margin analytics, valuation adjustment
  17.  *      analytics, and portfolio construction analytics within and across fixed income, credit, commodity,
  18.  *      equity, FX, and structured products. It also includes auxiliary libraries for algorithm support,
  19.  *      numerical analysis, numerical optimization, spline builder, model validation, statistical learning,
  20.  *      and computational support.
  21.  *  
  22.  *      https://lakshmidrip.github.io/DROP/
  23.  *  
  24.  *  DROP is composed of three modules:
  25.  *  
  26.  *  - DROP Product Core - https://lakshmidrip.github.io/DROP-Product-Core/
  27.  *  - DROP Portfolio Core - https://lakshmidrip.github.io/DROP-Portfolio-Core/
  28.  *  - DROP Computational Core - https://lakshmidrip.github.io/DROP-Computational-Core/
  29.  *
  30.  *  DROP Product Core implements libraries for the following:
  31.  *  - Fixed Income Analytics
  32.  *  - Loan Analytics
  33.  *  - Transaction Cost Analytics
  34.  *
  35.  *  DROP Portfolio Core implements libraries for the following:
  36.  *  - Asset Allocation Analytics
  37.  *  - Asset Liability Management Analytics
  38.  *  - Capital Estimation Analytics
  39.  *  - Exposure Analytics
  40.  *  - Margin Analytics
  41.  *  - XVA Analytics
  42.  *
  43.  *  DROP Computational Core implements libraries for the following:
  44.  *  - Algorithm Support
  45.  *  - Computation Support
  46.  *  - Function Analysis
  47.  *  - Model Validation
  48.  *  - Numerical Analysis
  49.  *  - Numerical Optimizer
  50.  *  - Spline Builder
  51.  *  - Statistical Learning
  52.  *
  53.  *  Documentation for DROP is Spread Over:
  54.  *
  55.  *  - Main                     => https://lakshmidrip.github.io/DROP/
  56.  *  - Wiki                     => https://github.com/lakshmiDRIP/DROP/wiki
  57.  *  - GitHub                   => https://github.com/lakshmiDRIP/DROP
  58.  *  - Repo Layout Taxonomy     => https://github.com/lakshmiDRIP/DROP/blob/master/Taxonomy.md
  59.  *  - Javadoc                  => https://lakshmidrip.github.io/DROP/Javadoc/index.html
  60.  *  - Technical Specifications => https://github.com/lakshmiDRIP/DROP/tree/master/Docs/Internal
  61.  *  - Release Versions         => https://lakshmidrip.github.io/DROP/version.html
  62.  *  - Community Credits        => https://lakshmidrip.github.io/DROP/credits.html
  63.  *  - Issues Catalog           => https://github.com/lakshmiDRIP/DROP/issues
  64.  *  - JUnit                    => https://lakshmidrip.github.io/DROP/junit/index.html
  65.  *  - Jacoco                   => https://lakshmidrip.github.io/DROP/jacoco/index.html
  66.  *
  67.  *  Licensed under the Apache License, Version 2.0 (the "License");
  68.  *      you may not use this file except in compliance with the License.
  69.  *  
  70.  *  You may obtain a copy of the License at
  71.  *      http://www.apache.org/licenses/LICENSE-2.0
  72.  *  
  73.  *  Unless required by applicable law or agreed to in writing, software
  74.  *      distributed under the License is distributed on an "AS IS" BASIS,
  75.  *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  76.  *  
  77.  *  See the License for the specific language governing permissions and
  78.  *      limitations under the License.
  79.  */

  80. /**
  81.  * <i>IncompleteEstimate</i> illustrates the Estimation of the Incomplete Beta Function. The References are:
  82.  *
  83.  * <br><br>
  84.  *  <ul>
  85.  *      <li>
  86.  *          Abramowitz, M., and I. A. Stegun (2007): <i>Handbook of Mathematics Functions</i> <b>Dover Book
  87.  *              on Mathematics</b>
  88.  *      </li>
  89.  *      <li>
  90.  *          Davis, P. J. (1959): Leonhard Euler's Integral: A Historical Profile of the Gamma Function
  91.  *              <i>American Mathematical Monthly</i> <b>66 (10)</b> 849-869
  92.  *      </li>
  93.  *      <li>
  94.  *          Whitaker, E. T., and G. N. Watson (1996): <i>A Course on Modern Analysis</i> <b>Cambridge
  95.  *              University Press</b> New York
  96.  *      </li>
  97.  *      <li>
  98.  *          Wikipedia (2019): Beta Function https://en.wikipedia.org/wiki/Beta_function
  99.  *      </li>
  100.  *      <li>
  101.  *          Wikipedia (2019): Gamma Function https://en.wikipedia.org/wiki/Gamma_function
  102.  *      </li>
  103.  *  </ul>
  104.  *
  105.  *  <br><br>
  106.  *  <ul>
  107.  *      <li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/ComputationalCore.md">Computational Core Module</a></li>
  108.  *      <li><b>Library</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/FunctionAnalysisLibrary.md">Function Analysis Library</a></li>
  109.  *      <li><b>Project</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/sample/README.md">DROP API Construction and Usage</a></li>
  110.  *      <li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/sample/beta/README.md">Estimates of the Beta Functions</a></li>
  111.  *  </ul>
  112.  *
  113.  * @author Lakshmi Krishnamurthy
  114.  */

  115. public class IncompleteEstimate
  116. {

  117.     private static final void Estimate (
  118.         final double[] xArray,
  119.         final double a,
  120.         final double b,
  121.         final R2ToR1 betaEstimator,
  122.         final R3ToR1 incompleteBetaEstimator)
  123.         throws Exception
  124.     {
  125.         String display =
  126.             "\t| [" +
  127.             FormatUtil.FormatDouble (a, 1, 1, 1., false) + ", " +
  128.             FormatUtil.FormatDouble (b, 1, 1, 1., false) + "] => " +
  129.             FormatUtil.FormatDouble (
  130.                 betaEstimator.evaluate (
  131.                     a,
  132.                     b
  133.                 ), 1, 8, 1., false
  134.             ) + " ||";

  135.         for (double x : xArray)
  136.         {
  137.             display = display +
  138.                 FormatUtil.FormatDouble (
  139.                     incompleteBetaEstimator.evaluate (
  140.                         x,
  141.                         a,
  142.                         b
  143.                     ), 1, 8, 1.
  144.                 ) + " |";
  145.         }

  146.         System.out.println (display + "|");
  147.     }

  148.     public static final void main (
  149.         final String[] argumentArray)
  150.         throws Exception
  151.     {
  152.         EnvManager.InitEnv ("");

  153.         double[] xArray =
  154.         {
  155.             1.00,
  156.             0.80,
  157.             0.60,
  158.             0.40,
  159.             0.20,
  160.             0.00,
  161.         };
  162.         double[] aArray =
  163.         {
  164.             1.,
  165.             2.,
  166.             3.,
  167.             4.,
  168.             5.,
  169.             6.,
  170.         };
  171.         double[] bArray =
  172.         {
  173.             1.,
  174.             2.,
  175.             3.,
  176.             4.,
  177.             5.,
  178.             6.,
  179.         };

  180.         int eulerIntegrandBetaTermCount = 1000;
  181.         int eulerIntegrandIncompleteBetaTermCount = 1000;

  182.         R2ToR1 betaEstimator = IntegrandEstimator.EulerFirstRightPlane (eulerIntegrandBetaTermCount);

  183.         R3ToR1 incompleteBetaEstimator = IncompleteIntegrandEstimator.EulerFirst
  184.             (eulerIntegrandIncompleteBetaTermCount);

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

  186.         System.out.println ("\t|                                    INCOMPLETE BETA FUNCTION ESTIMATE                                    ||");

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

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

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

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

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

  192.         System.out.println ("\t|                - Incomplete Beta Estimates for x E (1 ... 0)                                            ||");

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

  194.         for (double a : aArray)
  195.         {
  196.             for (double b : bArray)
  197.             {
  198.                 Estimate (
  199.                     xArray,
  200.                     a,
  201.                     b,
  202.                     betaEstimator,
  203.                     incompleteBetaEstimator
  204.                 );
  205.             }
  206.         }

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

  208.         EnvManager.TerminateEnv();
  209.     }
  210. }