LinearChargeBuyTerm.java

package org.drip.portfolioconstruction.objective;

/*
 * -*- 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 Krishnamurthy0
 * 
 *  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>LinearChargeBuyTerm</i> implements the Objective Term that optimizes the Charge incurred by the Buy
 * Trades in the Target Portfolio under a Linear Transaction Charge from the Starting Allocation.
 *
 *  <br><br>
 *  <ul>
 *      <li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/PortfolioCore.md">Portfolio Core Module</a></li>
 *      <li><b>Library</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/AssetAllocationAnalyticsLibrary.md">Asset Allocation Analytics</a></li>
 *      <li><b>Project</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/portfolioconstruction/README.md">Portfolio Construction under Allocation Constraints</a></li>
 *      <li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/portfolioconstruction/objective/README.md">Portfolio Construction Objective Term Suite</a></li>
 *  </ul>
 * <br><br>
 *
 * @author Lakshmi Krishnamurthy
 */

public class LinearChargeBuyTerm
    extends org.drip.portfolioconstruction.objective.TransactionChargeTerm
{

    /**
     * LinearChargeBuyTerm Conastructor
     * 
     * @param name Name of the Objective Term
     * @param initialHoldingsArray Initial Holdings
     * @param linearTransactionChargeArray Array of Linear Transaction Charge Instances
     * 
     * @throws java.lang.Exception Thrown if the Inputs are Invalid
     */

    public LinearChargeBuyTerm (
        final java.lang.String name,
        final double[] initialHoldingsArray,
        final org.drip.portfolioconstruction.cost.TransactionChargeLinear[] linearTransactionChargeArray)
        throws java.lang.Exception
    {
        super (
            name,
            "OT_LINEAR_BUY_TRANSACTION_CHARGE",
            "Linear Buy Only Transaction Charge Objective Function",
            initialHoldingsArray,
            linearTransactionChargeArray
        );
    }

    @Override public org.drip.function.definition.RdToR1 rdtoR1()
    {
        return new org.drip.function.definition.RdToR1 (null)
        {
            @Override public int dimension()
            {
                return initialHoldingsArray().length;
            }

            @Override public double evaluate (
                final double[] variateArray)
                throws java.lang.Exception
            {
                if (null == variateArray || !org.drip.numerical.common.NumberUtil.IsValid (variateArray))
                {
                    throw new java.lang.Exception ("LinearChargeBuyTerm::rdToR1::evaluate => Invalid Input");
                }

                org.drip.portfolioconstruction.cost.TransactionChargeLinear[] linearTransactionChargeArray =
                    (org.drip.portfolioconstruction.cost.TransactionChargeLinear[]) transactionChargeArray();

                double[] initialHoldingsArray = initialHoldingsArray();

                double linearChargeBuyTerm = 0.;
                int assetCount = linearTransactionChargeArray.length;

                if (variateArray.length != assetCount)
                {
                    throw new java.lang.Exception
                        ("LinearChargeBuyTerm::rdToR1::evaluate => Invalid Variate Dimension");
                }

                for (int assetIndex = 0; assetIndex < assetCount; ++assetIndex)
                {
                    if (variateArray[assetIndex] > initialHoldingsArray[assetIndex])
                    {
                        linearChargeBuyTerm += linearTransactionChargeArray[assetIndex].estimate (
                            initialHoldingsArray[assetIndex],
                            variateArray[assetIndex]
                        );
                    }
                }

                return linearChargeBuyTerm;
            }
        };
    }
}