ForwardDecompositionUtil.java

package org.drip.analytics.support;

/*
 * -*- 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
 * Copyright (C) 2014 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>ForwardDecompositionUtil</i> contains the utility functions needed to carry out periodic decomposition
 * at MTM sync points for the given stream.
 *
 *	<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/analytics/README.md">Date, Cash Flow, and Cash Flow Period Measure Generation Utilities</a></li>
 *		<li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/analytics/support/README.md">Assorted Support and Helper Utilities</a></li>
 *  </ul>
 * 
 * @author Lakshmi Krishnamurthy
 */

public class ForwardDecompositionUtil {

	/**
	 * Decompose the Stream into an Array of Single Forward Period Floating Streams
	 * 
	 * @param fs The Stream
	 * @param iNumPeriodsToAccumulate Number of Forward Periods to roll into one
	 * 
	 * @return The Array of Single Forward Period Streams
	 */

	public static final org.drip.product.rates.Stream[] SinglePeriodStreamDecompose (
		final org.drip.product.rates.Stream fs,
		final int iNumPeriodsToAccumulate)
	{
		if (null == fs) return null;

		java.util.List<org.drip.analytics.cashflow.CompositePeriod> lsCouponFlow = fs.cashFlowPeriod();

		int iNumPeriods = lsCouponFlow.size();

		int iCFPIndex = 0;
		int iNumPeriodsAccumulated = 0;
		int iNumForward = iNumPeriods / iNumPeriodsToAccumulate;
		org.drip.product.rates.Stream[] aFS = new org.drip.product.rates.Stream[iNumForward];

		java.util.List<java.util.List<org.drip.analytics.cashflow.CompositePeriod>> lslsCouponPeriod = new
			java.util.ArrayList<java.util.List<org.drip.analytics.cashflow.CompositePeriod>>();

		for (int i = 0; i < iNumForward; ++i)
			lslsCouponPeriod.add (new java.util.ArrayList<org.drip.analytics.cashflow.CompositePeriod>());

		for (org.drip.analytics.cashflow.CompositePeriod cfp : lsCouponFlow) {
			java.util.List<org.drip.analytics.cashflow.CompositePeriod> lsCouponPeriod = lslsCouponPeriod.get
				(iCFPIndex);

			lsCouponPeriod.add (cfp);

			if (++iNumPeriodsAccumulated != iNumPeriodsToAccumulate) continue;

			iNumPeriodsAccumulated = 0;

			try {
				aFS[iCFPIndex++] = new org.drip.product.rates.Stream (lsCouponPeriod);
			} catch (java.lang.Exception e) {
				e.printStackTrace();

				return null;
			}
		}

		return aFS;
	}

	/**
	 * Decompose the Dual Stream Component into an Array of Single Forward Period Dual Streams
	 * 
	 * @param dsc The Dual Stream
	 * 
	 * @return The Array of Single Forward Period Dual Streams
	 */

	public static final org.drip.product.definition.CalibratableComponent[] DualStreamForwardArray (
		final org.drip.product.rates.DualStreamComponent dsc)
	{
		if (null == dsc) return null;

		org.drip.product.rates.Stream streamDerived = dsc.derivedStream();

		org.drip.product.rates.Stream streamReference = dsc.referenceStream();

		int iNumForward = 0;
		org.drip.product.rates.Stream[] aStreamDerivedForward = null;
		org.drip.product.rates.Stream[] aStreamReferenceForward = null;

		int iDerivedStreamTenorMonths = 12 / streamDerived.freq();

		int iReferenceStreamTenorMonths = 12 / streamReference.freq();

		if (iReferenceStreamTenorMonths > iDerivedStreamTenorMonths) {
			if (null == (aStreamReferenceForward = SinglePeriodStreamDecompose (streamReference, 1)) || 0 ==
				(iNumForward = aStreamReferenceForward.length))
				return null;

			if (null == (aStreamDerivedForward = SinglePeriodStreamDecompose (streamDerived,
				iReferenceStreamTenorMonths / iDerivedStreamTenorMonths)) || iNumForward !=
					aStreamDerivedForward.length)
				return null;
		} else {
			if (null == (aStreamDerivedForward = SinglePeriodStreamDecompose (streamDerived, 1)) || 0 ==
				(iNumForward = aStreamDerivedForward.length))
				return null;

			if (null == (aStreamReferenceForward = SinglePeriodStreamDecompose (streamReference,
				iDerivedStreamTenorMonths / iReferenceStreamTenorMonths)) || iNumForward !=
					aStreamReferenceForward.length)
				return null;
		}

		org.drip.product.definition.CalibratableComponent[] aRC = new
			org.drip.product.definition.CalibratableComponent[iNumForward];

		for (int i = 0; i < iNumForward; ++i) {
			try {
				if (null == (aRC[i] = org.drip.product.creator.DualStreamComponentBuilder.MakeFloatFloat
					(aStreamReferenceForward[i], aStreamDerivedForward[i], new
						org.drip.param.valuation.CashSettleParams (0, streamDerived.couponCurrency(), 0))))
					return null;

				aRC[i].setPrimaryCode (streamReference.name() + "::" + streamDerived.name() + "_" + i);
			} catch (java.lang.Exception e) {
				e.printStackTrace();

				return null;
			}
		}

		return aRC;
	}

	/**
	 * Decompose the Rates Component into an Array of Single Forward Rates Components
	 * 
	 * @param rc The Rates Component
	 * 
	 * @return The Array of Single Forward Period Rates Components
	 */

	public static final org.drip.product.definition.CalibratableComponent[]
		CalibratableFixedIncomeComponentForwardArray (
			final org.drip.product.definition.CalibratableComponent rc)
	{
		return null != rc && rc instanceof org.drip.product.rates.DualStreamComponent ?
			DualStreamForwardArray ((org.drip.product.rates.DualStreamComponent) rc) : null;
	}
}