com.opengamma.analytics.financial.interestrate.payments.method.CapFloorIborHullWhiteMethod.java Source code

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/**
 * Copyright (C) 2011 - present by OpenGamma Inc. and the OpenGamma group of companies
 *
 * Please see distribution for license.
 */
package com.opengamma.analytics.financial.interestrate.payments.method;

import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang.Validate;

import com.opengamma.analytics.financial.interestrate.InstrumentDerivative;
import com.opengamma.analytics.financial.interestrate.InterestRateCurveSensitivity;
import com.opengamma.analytics.financial.interestrate.YieldCurveBundle;
import com.opengamma.analytics.financial.interestrate.method.PricingMethod;
import com.opengamma.analytics.financial.interestrate.payments.derivative.CapFloorIbor;
import com.opengamma.analytics.financial.model.interestrate.HullWhiteOneFactorPiecewiseConstantInterestRateModel;
import com.opengamma.analytics.financial.model.interestrate.definition.HullWhiteOneFactorPiecewiseConstantDataBundle;
import com.opengamma.analytics.math.statistics.distribution.NormalDistribution;
import com.opengamma.analytics.math.statistics.distribution.ProbabilityDistribution;
import com.opengamma.util.ArgumentChecker;
import com.opengamma.util.money.CurrencyAmount;
import com.opengamma.util.tuple.DoublesPair;

/**
 * Class used to compute the price and sensitivity of a Ibor cap/floor with
 * Hull-White one factor model.  The general pricing formula is given by:
 * $$
 * \begin{equation*}
 * \frac{\delta_p}{\delta_F}P^D(0,t_p)\left( \frac{P^j(0,t_0)}{P^j(0,t_1)} N(-\kappa-\alpha_0) - (1+\delta_F K) N(-\kappa-\alpha_1) \right)
 * \end{equation*}
 * $$
 * where:
 * \begin{equation*}
 * \kappa = \frac{1}{\alpha_1-\alpha_0} \left( \ln\left(\frac{(1+\delta_F K)P^j(0,t_1)}{P^j(0,t_0)}\right) - \frac12 (\alpha_1^2 - \alpha_0^2) \right).
 * \end{equation*}
 * $$
 *  @deprecated {@link HullWhiteOneFactorPiecewiseConstantDataBundle} is deprecated
 */
@Deprecated
public class CapFloorIborHullWhiteMethod implements PricingMethod {

    /**
     * The normal distribution.
     */
    private static final ProbabilityDistribution<Double> NORMAL = new NormalDistribution(0, 1);

    /**
     * The Hull-White model.
     */
    private final HullWhiteOneFactorPiecewiseConstantInterestRateModel _model = new HullWhiteOneFactorPiecewiseConstantInterestRateModel();

    /**
     * Constructor from the model.
     */
    public CapFloorIborHullWhiteMethod() {
    }

    /**
     * Computes the present value of a cap/floor in the Hull-White one factor model.
     * @param cap The cap/floor.
     * @param hwData The Hull-White parameters and the curves.
     * @return The present value.
     */
    public CurrencyAmount presentValue(final CapFloorIbor cap,
            final HullWhiteOneFactorPiecewiseConstantDataBundle hwData) {
        ArgumentChecker.notNull(cap, "The cap/floor shoud not be null");
        ArgumentChecker.notNull(hwData, "The Hull-White data shoud not be null");
        final double tp = cap.getPaymentTime();
        final double t0 = cap.getFixingPeriodStartTime();
        final double t1 = cap.getFixingPeriodEndTime();
        final double deltaF = cap.getFixingAccrualFactor();
        final double deltaP = cap.getPaymentYearFraction();
        final double k = cap.getStrike();
        final double dfPay = hwData.getCurve(cap.getFundingCurveName()).getDiscountFactor(tp);
        final double dfForwardT0 = hwData.getCurve(cap.getForwardCurveName()).getDiscountFactor(t0);
        final double dfForwardT1 = hwData.getCurve(cap.getForwardCurveName()).getDiscountFactor(t1);
        final double alpha0 = _model.alpha(hwData.getHullWhiteParameter(), 0.0, cap.getFixingTime(), tp, t0);
        final double alpha1 = _model.alpha(hwData.getHullWhiteParameter(), 0.0, cap.getFixingTime(), tp, t1);
        final double kappa = (Math.log((1 + deltaF * k) * dfForwardT1 / dfForwardT0)
                - (alpha1 * alpha1 - alpha0 * alpha0) / 2.0) / (alpha1 - alpha0);
        final double omega = (cap.isCap() ? 1.0 : -1.0);
        double pv = deltaP / deltaF * dfPay * omega
                * (dfForwardT0 / dfForwardT1 * NORMAL.getCDF(omega * (-kappa - alpha0))
                        - (1.0 + deltaF * k) * NORMAL.getCDF(omega * (-kappa - alpha1)));
        pv *= cap.getNotional();
        return CurrencyAmount.of(cap.getCurrency(), pv);
    }

    @Override
    public CurrencyAmount presentValue(final InstrumentDerivative instrument, final YieldCurveBundle curves) {
        Validate.isTrue(instrument instanceof CapFloorIbor, "Ibor Cap/floor");
        Validate.isTrue(curves instanceof HullWhiteOneFactorPiecewiseConstantDataBundle,
                "Bundle should contain Hull-White data");
        return presentValue((CapFloorIbor) instrument, (HullWhiteOneFactorPiecewiseConstantDataBundle) curves);
    }

    /**
     * Computes the present value curve sensitivity of a cap/floor in the Hull-White one factor model.
     * @param cap The cap/floor.
     * @param hwData The Hull-White parameters and the curves.
     * @return The present value curve sensitivity.
     */
    public InterestRateCurveSensitivity presentValueCurveSensitivity(final CapFloorIbor cap,
            final HullWhiteOneFactorPiecewiseConstantDataBundle hwData) {
        ArgumentChecker.notNull(cap, "The cap/floor shoud not be null");
        ArgumentChecker.notNull(hwData, "The Hull-White data shoud not be null");
        final double tp = cap.getPaymentTime();
        final double t0 = cap.getFixingPeriodStartTime();
        final double t1 = cap.getFixingPeriodEndTime();
        final double deltaF = cap.getFixingAccrualFactor();
        final double deltaP = cap.getPaymentYearFraction();
        final double k = cap.getStrike();
        final double omega = (cap.isCap() ? 1.0 : -1.0);
        // Forward sweep
        final double dfPay = hwData.getCurve(cap.getFundingCurveName()).getDiscountFactor(tp);
        final double dfForwardT0 = hwData.getCurve(cap.getForwardCurveName()).getDiscountFactor(t0);
        final double dfForwardT1 = hwData.getCurve(cap.getForwardCurveName()).getDiscountFactor(t1);
        final double alpha0 = _model.alpha(hwData.getHullWhiteParameter(), 0.0, cap.getFixingTime(), tp, t0);
        final double alpha1 = _model.alpha(hwData.getHullWhiteParameter(), 0.0, cap.getFixingTime(), tp, t1);
        final double kappa = (Math.log((1 + deltaF * k) * dfForwardT1 / dfForwardT0)
                - (alpha1 * alpha1 - alpha0 * alpha0) / 2.0) / (alpha1 - alpha0);
        final double n0 = NORMAL.getCDF(omega * (-kappa - alpha0));
        final double n1 = NORMAL.getCDF(omega * (-kappa - alpha1));
        //    double pv = deltaP / deltaF * dfPay * omega * (dfForwardT0 / dfForwardT1 * n0 - (1.0 + deltaF * k) * n1) * cap.getNotional();
        // Backward sweep
        final double pvBar = 1.0;
        //    double kappaBar = 0.0; // kappa is the optimal exercise boundary
        final double dfForwardT1Bar = -deltaP / deltaF * dfPay * omega * dfForwardT0 / (dfForwardT1 * dfForwardT1)
                * n0 * cap.getNotional() * pvBar;
        final double dfForwardT0Bar = deltaP / deltaF * dfPay * omega / dfForwardT1 * n0 * cap.getNotional()
                * pvBar;
        final double dfPayBar = deltaP / deltaF * omega * (dfForwardT0 / dfForwardT1 * n0 - (1.0 + deltaF * k) * n1)
                * cap.getNotional() * pvBar;
        InterestRateCurveSensitivity result = new InterestRateCurveSensitivity();
        final List<DoublesPair> listDiscounting = new ArrayList<>();
        listDiscounting.add(new DoublesPair(cap.getPaymentTime(), -cap.getPaymentTime() * dfPay * dfPayBar));
        result = result.plus(cap.getFundingCurveName(), listDiscounting);
        final List<DoublesPair> listForward = new ArrayList<>();
        listForward.add(new DoublesPair(cap.getFixingPeriodStartTime(),
                -cap.getFixingPeriodStartTime() * dfForwardT0 * dfForwardT0Bar));
        listForward.add(new DoublesPair(cap.getFixingPeriodEndTime(),
                -cap.getFixingPeriodEndTime() * dfForwardT1 * dfForwardT1Bar));
        result = result.plus(cap.getForwardCurveName(), listForward);
        return result;
    }

    /**
     * Computes the present value Hull-White parameters sensitivity of a cap/floor in the Hull-White one factor model.
     * @param cap The cap/floor.
     * @param hwData The Hull-White parameters and the curves.
     * @return The present value parameters sensitivity.
     */
    public double[] presentValueHullWhiteSensitivity(final CapFloorIbor cap,
            final HullWhiteOneFactorPiecewiseConstantDataBundle hwData) {
        ArgumentChecker.notNull(cap, "The cap/floor shoud not be null");
        ArgumentChecker.notNull(hwData, "The Hull-White data shoud not be null");
        final double tp = cap.getPaymentTime();
        final double[] t = new double[2];
        t[0] = cap.getFixingPeriodStartTime();
        t[1] = cap.getFixingPeriodEndTime();
        final double deltaF = cap.getFixingAccrualFactor();
        final double deltaP = cap.getPaymentYearFraction();
        final double k = cap.getStrike();
        final double omega = (cap.isCap() ? 1.0 : -1.0);
        // Forward sweep
        final double dfPay = hwData.getCurve(cap.getFundingCurveName()).getDiscountFactor(tp);
        final double dfForwardT0 = hwData.getCurve(cap.getForwardCurveName()).getDiscountFactor(t[0]);
        final double dfForwardT1 = hwData.getCurve(cap.getForwardCurveName()).getDiscountFactor(t[1]);
        final int nbSigma = hwData.getHullWhiteParameter().getVolatility().length;
        final double[] alpha = new double[2];
        final double[][] alphaDerivatives = new double[2][nbSigma];
        for (int loopcf = 0; loopcf < 2; loopcf++) {
            alpha[loopcf] = _model.alpha(hwData.getHullWhiteParameter(), 0.0, cap.getFixingTime(), tp, t[loopcf],
                    alphaDerivatives[loopcf]);
        }
        final double kappa = (Math.log((1 + deltaF * k) * dfForwardT1 / dfForwardT0)
                - (alpha[1] * alpha[1] - alpha[0] * alpha[0]) / 2.0) / (alpha[1] - alpha[0]);
        final double[] n = new double[2];
        for (int loopcf = 0; loopcf < 2; loopcf++) {
            n[loopcf] = NORMAL.getCDF(omega * (-kappa - alpha[loopcf]));
        }
        //    double pv = deltaP / deltaF * dfPay * omega * (dfForwardT0 / dfForwardT1 * n0 - (1.0 + deltaF * k) * n1) * cap.getNotional();
        // Backward sweep
        final double pvBar = 1.0;
        final double[] nBar = new double[2];
        nBar[1] = deltaP / deltaF * dfPay * omega * (1.0 + deltaF * k) * cap.getNotional() * pvBar;
        nBar[0] = deltaP / deltaF * dfPay * omega * dfForwardT0 / dfForwardT1 * cap.getNotional();
        final double[] alphaBar = new double[2];
        for (int loopcf = 0; loopcf < 2; loopcf++) {
            alphaBar[loopcf] = NORMAL.getPDF(omega * (-kappa - alpha[loopcf])) * -omega * nBar[loopcf];
        }
        final double[] sigmaBar = new double[nbSigma];
        for (int loopcf = 0; loopcf < 2; loopcf++) {
            for (int loopsigma = 0; loopsigma < nbSigma; loopsigma++) {
                sigmaBar[loopsigma] += alphaDerivatives[loopcf][loopsigma] * alphaBar[loopcf];
            }
        }
        return sigmaBar;
    }

}