R0ToR1Series.java

  1. package org.drip.numerical.estimation;

  2. /*
  3.  * -*- mode: java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  4.  */

  5. /*!
  6.  * Copyright (C) 2020 Lakshmi Krishnamurthy
  7.  * Copyright (C) 2019 Lakshmi Krishnamurthy
  8.  *
  9.  *  This file is part of DROP, an open-source library targeting analytics/risk, transaction cost analytics,
  10.  *      asset liability management analytics, capital, exposure, and margin analytics, valuation adjustment
  11.  *      analytics, and portfolio construction analytics within and across fixed income, credit, commodity,
  12.  *      equity, FX, and structured products. It also includes auxiliary libraries for algorithm support,
  13.  *      numerical analysis, numerical optimization, spline builder, model validation, statistical learning,
  14.  *      and computational support.
  15.  *  
  16.  *      https://lakshmidrip.github.io/DROP/
  17.  *  
  18.  *  DROP is composed of three modules:
  19.  *  
  20.  *  - DROP Product Core - https://lakshmidrip.github.io/DROP-Product-Core/
  21.  *  - DROP Portfolio Core - https://lakshmidrip.github.io/DROP-Portfolio-Core/
  22.  *  - DROP Computational Core - https://lakshmidrip.github.io/DROP-Computational-Core/
  23.  *
  24.  *  DROP Product Core implements libraries for the following:
  25.  *  - Fixed Income Analytics
  26.  *  - Loan Analytics
  27.  *  - Transaction Cost Analytics
  28.  *
  29.  *  DROP Portfolio Core implements libraries for the following:
  30.  *  - Asset Allocation Analytics
  31.  *  - Asset Liability Management Analytics
  32.  *  - Capital Estimation Analytics
  33.  *  - Exposure Analytics
  34.  *  - Margin Analytics
  35.  *  - XVA Analytics
  36.  *
  37.  *  DROP Computational Core implements libraries for the following:
  38.  *  - Algorithm Support
  39.  *  - Computation Support
  40.  *  - Function Analysis
  41.  *  - Model Validation
  42.  *  - Numerical Analysis
  43.  *  - Numerical Optimizer
  44.  *  - Spline Builder
  45.  *  - Statistical Learning
  46.  *
  47.  *  Documentation for DROP is Spread Over:
  48.  *
  49.  *  - Main                     => https://lakshmidrip.github.io/DROP/
  50.  *  - Wiki                     => https://github.com/lakshmiDRIP/DROP/wiki
  51.  *  - GitHub                   => https://github.com/lakshmiDRIP/DROP
  52.  *  - Repo Layout Taxonomy     => https://github.com/lakshmiDRIP/DROP/blob/master/Taxonomy.md
  53.  *  - Javadoc                  => https://lakshmidrip.github.io/DROP/Javadoc/index.html
  54.  *  - Technical Specifications => https://github.com/lakshmiDRIP/DROP/tree/master/Docs/Internal
  55.  *  - Release Versions         => https://lakshmidrip.github.io/DROP/version.html
  56.  *  - Community Credits        => https://lakshmidrip.github.io/DROP/credits.html
  57.  *  - Issues Catalog           => https://github.com/lakshmiDRIP/DROP/issues
  58.  *  - JUnit                    => https://lakshmidrip.github.io/DROP/junit/index.html
  59.  *  - Jacoco                   => https://lakshmidrip.github.io/DROP/jacoco/index.html
  60.  *
  61.  *  Licensed under the Apache License, Version 2.0 (the "License");
  62.  *      you may not use this file except in compliance with the License.
  63.  *  
  64.  *  You may obtain a copy of the License at
  65.  *      http://www.apache.org/licenses/LICENSE-2.0
  66.  *  
  67.  *  Unless required by applicable law or agreed to in writing, software
  68.  *      distributed under the License is distributed on an "AS IS" BASIS,
  69.  *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  70.  *  
  71.  *  See the License for the specific language governing permissions and
  72.  *      limitations under the License.
  73.  */

  74. /**
  75.  * <i>R0ToR1Series</i> generates a Series of Weighted Numerical R<sup>0</sup> To R<sup>1</sup> Terms. The
  76.  * References are:
  77.  *
  78.  * <br><br>
  79.  *  <ul>
  80.  *      <li>
  81.  *          Mortici, C. (2011): Improved Asymptotic Formulas for the Gamma Function <i>Computers and
  82.  *              Mathematics with Applications</i> <b>61 (11)</b> 3364-3369
  83.  *      </li>
  84.  *      <li>
  85.  *          National Institute of Standards and Technology (2018): NIST Digital Library of Mathematical
  86.  *              Functions https://dlmf.nist.gov/5.11
  87.  *      </li>
  88.  *      <li>
  89.  *          Nemes, G. (2010): On the Coefficients of the Asymptotic Expansion of n!
  90.  *              https://arxiv.org/abs/1003.2907 <b>arXiv</b>
  91.  *      </li>
  92.  *      <li>
  93.  *          Toth V. T. (2016): Programmable Calculators – The Gamma Function
  94.  *              http://www.rskey.org/CMS/index.php/the-library/11
  95.  *      </li>
  96.  *      <li>
  97.  *          Wikipedia (2019): Stirling's Approximation
  98.  *              https://en.wikipedia.org/wiki/Stirling%27s_approximation
  99.  *      </li>
  100.  *  </ul>
  101.  *
  102.  *  <br><br>
  103.  *  <ul>
  104.  *      <li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/ComputationalCore.md">Computational Core Module</a></li>
  105.  *      <li><b>Library</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/NumericalAnalysisLibrary.md">Numerical Analysis Library</a></li>
  106.  *      <li><b>Project</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/numerical/README.md">Numerical Quadrature, Differentiation, Eigenization, Linear Algebra, and Utilities</a></li>
  107.  *      <li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/numerical/estimation/README.md">Function Numerical Estimates/Corrections/Bounds</a></li>
  108.  *  </ul>
  109.  *
  110.  * @author Lakshmi Krishnamurthy
  111.  */

  112. public class R0ToR1Series extends org.drip.numerical.estimation.RxToR1Series
  113. {
  114.     private boolean _cumulative = false;
  115.     private org.drip.numerical.estimation.R0ToR1SeriesTerm _r0Tor1SeriesTerm = null;

  116.     /**
  117.      * R0ToR1Series Constructor
  118.      *
  119.      * @param r0Tor1SeriesTerm R<sup>0</sup> To R<sup>1</sup> Series Term
  120.      * @param proportional TRUE - The Series Term is Proportional
  121.      * @param termWeightMap Error Term Weight Map
  122.      * @param cumulative TRUE - The Series Term is Cumulative
  123.      *
  124.      * @throws java.lang.Exception Thrown if the Inputs are Invalid
  125.      */

  126.     public R0ToR1Series (
  127.         final org.drip.numerical.estimation.R0ToR1SeriesTerm r0Tor1SeriesTerm,
  128.         final boolean proportional,
  129.         final java.util.TreeMap<java.lang.Integer, java.lang.Double> termWeightMap,
  130.         final boolean cumulative)
  131.         throws java.lang.Exception
  132.     {
  133.         super (
  134.             proportional,
  135.             termWeightMap
  136.         );

  137.         if (null == (_r0Tor1SeriesTerm = r0Tor1SeriesTerm))
  138.         {
  139.             throw new java.lang.Exception ("R0ToR1Series Constructor => Invalid Inputs");
  140.         }

  141.         _cumulative = cumulative;
  142.     }

  143.     /**
  144.      * Retrieve the R<sup>0</sup> To R<sup>1</sup> Series Term
  145.      *
  146.      * @return The R<sup>0</sup> To R<sup>1</sup> Series Term
  147.      */

  148.     public org.drip.numerical.estimation.R0ToR1SeriesTerm r0Tor1SeriesTerm()
  149.     {
  150.         return _r0Tor1SeriesTerm;
  151.     }

  152.     /**
  153.      * Indicate if the Series Term is Incremental or Cumulative
  154.      *
  155.      * @return TRUE - The Series Term is Cumulative
  156.      */

  157.     public boolean cumulative()
  158.     {
  159.         return _cumulative;
  160.     }

  161.     /**
  162.      * Generate the Series Expansion using the R<sup>0</sup> To R<sup>1</sup> Term
  163.      *
  164.      * @param zeroOrder The Zero Order Estimate
  165.      *
  166.      * @return The Series Expansion
  167.      */

  168.     public java.util.TreeMap<java.lang.Integer, java.lang.Double> generate (
  169.         final double zeroOrder)
  170.     {
  171.         if (!org.drip.numerical.common.NumberUtil.IsValid (zeroOrder))
  172.         {
  173.             return null;
  174.         }

  175.         java.util.TreeMap<java.lang.Integer, java.lang.Double> seriesExpansionMap = new
  176.             java.util.TreeMap<java.lang.Integer, java.lang.Double>();

  177.         java.util.TreeMap<java.lang.Integer, java.lang.Double> termWeightMap = termWeightMap();

  178.         if (null == termWeightMap || 0 == termWeightMap.size())
  179.         {
  180.             return seriesExpansionMap;
  181.         }

  182.         double scale = proportional() ? zeroOrder : 1.;

  183.         double seriesValue = 0.;

  184.         for (java.util.Map.Entry<java.lang.Integer, java.lang.Double> termWeightEntry :
  185.             termWeightMap.entrySet())
  186.         {
  187.             int order = termWeightEntry.getKey();

  188.             try
  189.             {
  190.                 double orderSeriesValue = scale * termWeightEntry.getValue() * _r0Tor1SeriesTerm.value
  191.                     (order);

  192.                 seriesExpansionMap.put (
  193.                     order,
  194.                     _cumulative ? (seriesValue = seriesValue + orderSeriesValue) : orderSeriesValue
  195.                 );
  196.             }
  197.             catch (java.lang.Exception e)
  198.             {
  199.                 e.printStackTrace();

  200.                 return null;
  201.             }
  202.         }

  203.         return seriesExpansionMap;
  204.     }

  205.     @Override public double evaluate (
  206.         final double x)
  207.         throws java.lang.Exception
  208.     {
  209.         java.util.TreeMap<java.lang.Integer, java.lang.Double> termWeightMap = termWeightMap();

  210.         if (null == termWeightMap || 0 == termWeightMap.size())
  211.         {
  212.             return 0.;
  213.         }

  214.         double scale = proportional() ? 0. : 1.;

  215.         double value = 0.;
  216.         double seriesValue = 0.;

  217.         for (java.util.Map.Entry<java.lang.Integer, java.lang.Double> termWeightEntry :
  218.             termWeightMap.entrySet())
  219.         {
  220.             int order = termWeightEntry.getKey();

  221.             double orderSeriesValue = scale * termWeightEntry.getValue() * _r0Tor1SeriesTerm.value
  222.                 (order);

  223.             value = value + (_cumulative ? (seriesValue = seriesValue + orderSeriesValue) :
  224.                 orderSeriesValue);
  225.         }

  226.         return value;
  227.     }

  228.     @Override public double derivative (
  229.         final double x,
  230.         final int order)
  231.         throws java.lang.Exception
  232.     {
  233.         return 0.;
  234.     }
  235. }