FlatForwardRepoCurve.java

package org.drip.state.nonlinear;

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

/*!
 * Copyright (C) 2020 Lakshmi Krishnamurthy
 * Copyright (C) 2019 Lakshmi Krishnamurthy
 * Copyright (C) 2018 Lakshmi Krishnamurthy
 * Copyright (C) 2017 Lakshmi Krishnamurthy
 * Copyright (C) 2016 Lakshmi Krishnamurthy
 * Copyright (C) 2015 Lakshmi Krishnamurthy
 * 
 *  This file is part of DROP, an open-source library targeting analytics/risk, transaction cost analytics,
 *      asset liability management analytics, capital, exposure, and margin analytics, valuation adjustment
 *      analytics, and portfolio construction analytics within and across fixed income, credit, commodity,
 *      equity, FX, and structured products. It also includes auxiliary libraries for algorithm support,
 *      numerical analysis, numerical optimization, spline builder, model validation, statistical learning,
 *      and computational support.
 *  
 *      https://lakshmidrip.github.io/DROP/
 *  
 *  DROP is composed of three modules:
 *  
 *  - DROP Product Core - https://lakshmidrip.github.io/DROP-Product-Core/
 *  - DROP Portfolio Core - https://lakshmidrip.github.io/DROP-Portfolio-Core/
 *  - DROP Computational Core - https://lakshmidrip.github.io/DROP-Computational-Core/
 * 
 *  DROP Product Core implements libraries for the following:
 *  - Fixed Income Analytics
 *  - Loan Analytics
 *  - Transaction Cost Analytics
 * 
 *  DROP Portfolio Core implements libraries for the following:
 *  - Asset Allocation Analytics
 *  - Asset Liability Management Analytics
 *  - Capital Estimation Analytics
 *  - Exposure Analytics
 *  - Margin Analytics
 *  - XVA Analytics
 * 
 *  DROP Computational Core implements libraries for the following:
 *  - Algorithm Support
 *  - Computation Support
 *  - Function Analysis
 *  - Model Validation
 *  - Numerical Analysis
 *  - Numerical Optimizer
 *  - Spline Builder
 *  - Statistical Learning
 * 
 *  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>FlatForwardRepoCurve</i> manages the Repo Latent State, using the Forward Repo Rate as the State
 * Response Representation.
 *
 *  <br><br>
 *  <ul>
 *      <li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/ProductCore.md">Product 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/state/README.md">Latent State Inference and Creation Utilities</a></li>
 *      <li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/state/nonlinear/README.md">Nonlinear (i.e., Boot) Latent State Construction</a></li>
 *  </ul>
 * <br><br>
 *
 * @author Lakshmi Krishnamurthy
 */

public class FlatForwardRepoCurve extends org.drip.state.repo.ExplicitBootRepoCurve {
    private int[] _aiPillarDate = null;
    private double[] _adblRepoForward = null;

    /**
     * FlatForwardRepoCurve Constructor
     * 
     * @param iEpochDate Epoch Date
     * @param comp The Repo Component
     * @param aiPillarDate Array of Pillar Dates
     * @param adblRepoForward Array of Repo Forward Rates
     * 
     * @throws java.lang.Exception Thrown if the Inputs are Invalid
     */

    public FlatForwardRepoCurve (
        final int iEpochDate,
        final org.drip.product.definition.Component comp,
        final int[] aiPillarDate,
        final double[] adblRepoForward)
        throws java.lang.Exception
    {
        super (iEpochDate, comp);

        if (null == (_aiPillarDate = aiPillarDate) || null == (_adblRepoForward = adblRepoForward) ||
            _aiPillarDate.length != _adblRepoForward.length)
            throw new java.lang.Exception ("FlatForwardRepoCurve ctr => Invalid Inputs");

        int iNumPillar = _aiPillarDate.length;

        for (int i = 0; i < iNumPillar; ++i) {
            if (!org.drip.numerical.common.NumberUtil.IsValid (_aiPillarDate[i]) ||
                !org.drip.numerical.common.NumberUtil.IsValid (_adblRepoForward[i]))
                throw new java.lang.Exception ("FlatForwardRepoCurve ctr => Invalid Inputs");
        }
    }

    @Override public double repo (
        final int iDate)
        throws java.lang.Exception
    {
        if (iDate >= component().maturityDate().julian())
            throw new java.lang.Exception ("FlatForwardRepoCurve::repo => Invalid Input");

        if (iDate <= epoch().julian()) return _adblRepoForward[0];

        int iNumPillar = _adblRepoForward.length;

        for (int i = 1; i < iNumPillar; ++i) {
            if (_aiPillarDate[i - 1] <= iDate && _aiPillarDate[i] > iDate)
                return _adblRepoForward[i];
        }

        return _adblRepoForward[iNumPillar - 1];
    }

    @Override public boolean setNodeValue (
        final int iNodeIndex,
        final double dblValue)
    {
        if (!org.drip.numerical.common.NumberUtil.IsValid (dblValue) || iNodeIndex > _adblRepoForward.length)
            return false;

        for (int i = iNodeIndex; i < _adblRepoForward.length; ++i)
            _adblRepoForward[i] = dblValue;

        return true;
    }

    @Override public boolean bumpNodeValue (
        final int iNodeIndex,
        final double dblValue)
    {
        if (!org.drip.numerical.common.NumberUtil.IsValid (dblValue) || iNodeIndex > _adblRepoForward.length)
            return false;

        for (int i = iNodeIndex; i < _adblRepoForward.length; ++i)
            _adblRepoForward[i] += dblValue;

        return true;
    }

    @Override public boolean setFlatValue (
        final double dblValue)
    {
        if (!org.drip.numerical.common.NumberUtil.IsValid (dblValue)) return false;

        for (int i = 0; i < _adblRepoForward.length; ++i)
            _adblRepoForward[i] = dblValue;

        return true;
    }
}