public PremiumLegElement(double protectionStart, CdsCoupon coupon, YieldTermStructure yieldCurve, int creditCurveKnot, double[] knots, AccrualOnDefaultFormulae formula) : base(coupon, yieldCurve, creditCurveKnot) { _coupon = coupon; _creditCurveKnot = creditCurveKnot; _formula = formula; if (formula == AccrualOnDefaultFormulae.ORIGINAL_ISDA) { _omega = 1.0 / 730; } else { _omega = 0.0; } _knots = DoublesScheduleGenerator.truncateSetInclusive(Math.Max(_coupon.getEffStart(), protectionStart), _coupon.getEffEnd(), knots); _n = _knots.Length; _rt = new double[_n]; _p = new double[_n]; for (int i = 0; i < _n; i++) { _rt[i] = yieldCurve.getRT_(_knots[i]); _p[i] = Math.Exp(-_rt[i]); } }
private double calculateSinglePeriodAccrualOnDefault( CdsCoupon coupon, double effectiveStart, double[] integrationPoints, YieldTermStructure yieldCurve, PiecewiseconstantHazardRate creditCurve) { double start = Math.Max(coupon.getEffStart(), effectiveStart); if (start >= coupon.getEffEnd()) { return(0.0); //this coupon has already expired } double[] knots = DoublesScheduleGenerator.truncateSetInclusive(start, coupon.getEffEnd(), integrationPoints); double t = knots[0]; double ht0 = creditCurve.getRT_(t); double rt0 = yieldCurve.getRT_(t); double b0 = Math.Exp(-rt0 - ht0); // this is the risky discount factor double t0 = t - coupon.getEffStart() + _omega; double pv = 0.0; int nItems = knots.Length; for (int j = 1; j < nItems; ++j) { t = knots[j]; double ht1 = creditCurve.getRT_(t); double rt1 = yieldCurve.getRT_(t); double b1 = Math.Exp(-rt1 - ht1); double dt = knots[j] - knots[j - 1]; double dht = ht1 - ht0; double drt = rt1 - rt0; double dhrt = dht + drt; double tPV; double t1 = t - coupon.getEffStart() + _omega; if (Math.Abs(dhrt) < 1e-5) { tPV = dht * b0 * (t0 * Maths.Epsilon.epsilon(-dhrt) + dt * Maths.Epsilon.epsilonP(-dhrt)); } else { tPV = dht / dhrt * (t0 * b0 - t1 * b1 + dt / dhrt * (b0 - b1)); } t0 = t1; pv += tPV; ht0 = ht1; rt0 = rt1; b0 = b1; } return(coupon.getYFRatio() * pv); }
public ProtectionLegElement(double start, double end, YieldTermStructure yieldCurve, int creditCurveKnot, double[] knots) { _knots = DoublesScheduleGenerator.truncateSetInclusive(start, end, knots); _n = _knots.Length; _rt = new double[_n]; _p = new double[_n]; for (int i = 0; i < _n; i++) { _rt[i] = yieldCurve.getRT_(_knots[i]); _p[i] = Math.Exp(-_rt[i]); } _creditCurveKnot = creditCurveKnot; }
public double pvPremiumLegCreditSensitivity( CDS cds, YieldTermStructure yieldCurve, PiecewiseconstantHazardRate creditCurve, int creditCurveNode) { if (cds.getProtectionEnd() <= 0.0) { //short cut already expired CDSs return(0.0); } int n = cds.getNumPayments(); double pvSense = 0.0; for (int i = 0; i < n; i++) { CdsCoupon c = cds.getCoupon(i); double paymentTime = c.getPaymentTime(); double creditObsTime = c.getEffEnd(); double dqdh = creditCurve.getSingleNodeDiscountFactorSensitivity(creditObsTime, creditCurveNode); if (dqdh == 0) { continue; } double p = Math.Exp(-yieldCurve.getRT_(paymentTime)); pvSense += c.getYearFrac() * p * dqdh; } if (cds.isPayAccOnDefault()) { double start = cds.getNumPayments() == 1 ? cds.getEffectiveProtectionStart() : cds.getAccStart(); double[] integrationSchedule = DoublesScheduleGenerator.getIntegrationsPoints(start, cds.getProtectionEnd(), yieldCurve, creditCurve); double accPVSense = 0.0; for (int i = 0; i < n; i++) { accPVSense += calculateSinglePeriodAccrualOnDefaultCreditSensitivity( cds.getCoupon(i), cds.getEffectiveProtectionStart(), integrationSchedule, yieldCurve, creditCurve, creditCurveNode); } pvSense += accPVSense; } double df = Math.Exp(-yieldCurve.getRT_(cds.getCashSettleTime())); pvSense /= df; return(pvSense); }
/** * The value of the full (or dirty) annuity (or RPV01 - the premium leg per unit of coupon) today (t=0). * The cash flows from premium payments and accrual-on-default are risky discounted to t=0 * The actual value of the leg is this multiplied by the notional and the fractional coupon * (i.e. coupon in basis points divided by 10,000). * <p> * This is valid for both spot and forward starting CDS. * * @param cds the analytic description of a CDS traded at a certain time * @param yieldCurve the yield (or discount) curve * @param creditCurve the credit (or survival) curve * @return the full (or dirty) annuity valued today. <b>Note</b> what is usually quoted is the clean annuity */ public double dirtyAnnuity(CDS cds, YieldTermStructure yt, PiecewiseconstantHazardRate hazard) { DateTime tradedate = cds.tradedate; List <DateTime> Jumps = yt.jumpDates_; DateTime settlementDate = tradedate.AddDays(0); double recoveryrate = cds.Recovery; DateTime Stepindate = tradedate.AddDays(1); double coupon = cds.PremiumRate; OMLib.Conventions.DayCount.Actual360 dc = new OMLib.Conventions.DayCount.Actual360(); CdsCoupon[] cf = cds.getCoupons(); double notional = cds.Notional; double ita = (double)365 / 360; double totalNPV = 0.0; for (int i = 0; i < cf.Length; ++i) { totalNPV += cf[i].getYearFrac() * notional * Math.Exp(-hazard.getRT_(cf[i].getEffEnd())) * Math.Exp(-yt.getRT_(cf[i].getPaymentTime())); } double start = cds.getNumPayments() == 1 ? cds.getEffectiveProtectionStart() : cds.getAccStart(); double[] integrationSchedule = DoublesScheduleGenerator.getIntegrationsPoints(start, cds.getProtectionEnd(), yt, hazard); double accPV = 0.0; for (int i = 0; i < cf.Length; ++i) { accPV += calculateSinglePeriodAccrualOnDefault(cf[i], cds.getEffectiveProtectionStart(), integrationSchedule, yt, hazard); } totalNPV += accPV; return(totalNPV); }
public IntrinsicIndexDataBundle adjustCurves( double[] indexPUF, CDS[] indexCDS, double indexCoupon, YieldTermStructure yieldCurve, IntrinsicIndexDataBundle intrinsicData) { int nIndexTerms = indexCDS.Length; if (nIndexTerms == 1) { return(adjustCurves(indexPUF[0], indexCDS[0], indexCoupon, yieldCurve, intrinsicData)); } double[] indexKnots = new double[nIndexTerms]; for (int i = 0; i < nIndexTerms; i++) { indexKnots[i] = indexCDS[i].getProtectionEnd(); } PiecewiseconstantHazardRate[] creditCurves = intrinsicData.getCreditCurves(); int nCurves = creditCurves.Length; //we cannot assume that all the credit curves have knots at the same times or that the terms of the indices fall on these knots. PiecewiseconstantHazardRate[] modCreditCurves = new PiecewiseconstantHazardRate[nCurves]; int[,] indexMap = new int[nCurves, nIndexTerms]; for (int i = 0; i < nCurves; i++) { if (creditCurves[i] == null) { modCreditCurves[i] = null; //null credit curves correspond to defaulted names, so are ignored } else { double[] ccKnots = creditCurves[i].t.ToArray(); double[] comKnots = DoublesScheduleGenerator.combineSets(ccKnots, indexKnots); int nKnots = comKnots.Length; if (nKnots == ccKnots.Length) { modCreditCurves[i] = creditCurves[i]; } else { double[] rt = new double[nKnots]; for (int j = 0; j < nKnots; j++) { rt[j] = creditCurves[i].getRT_(comKnots[j]); } PiecewiseconstantHazardRate hazard = new PiecewiseconstantHazardRate(creditCurves[i].latestReference_, null, null, null, null); modCreditCurves[i] = hazard.makeFromRT(comKnots.ToList(), rt); } for (int j = 0; j < nIndexTerms; j++) { int index = Array.BinarySearch(modCreditCurves[i].t.ToArray(), indexKnots[j]); indexMap[i, j] = index; } } } int[] startKnots = new int[nCurves]; int[] endKnots = new int[nCurves]; double alpha = 1.0; for (int i = 0; i < nIndexTerms; i++) { if (i == (nIndexTerms - 1)) { for (int jj = 0; jj < nCurves; jj++) { if (modCreditCurves[jj] != null) { endKnots[jj] = modCreditCurves[jj].t.Count; } } } else { for (int jj = 0; jj < nCurves; jj++) { if (modCreditCurves[jj] != null) { endKnots[jj] = indexMap[jj, i] + 1; } } } IntrinsicIndexDataBundle modIntrinsicData = intrinsicData.withCreditCurves(modCreditCurves); Func <double, double> func = getHazardRateAdjFunction(indexPUF[i], indexCDS[i], indexCoupon, yieldCurve, modIntrinsicData, startKnots, endKnots); alpha = ROOTFINDER.getRoot(func, alpha); modCreditCurves = adjustCurves(modCreditCurves, alpha, startKnots, endKnots); startKnots = endKnots; } return(intrinsicData.withCreditCurves(modCreditCurves)); }
public CreditCurveCalibrator(MultiCdsAnalytic multiCDS, YieldTermStructure yieldCurve, AccrualOnDefaultFormulae formula) { _nCDS = multiCDS.getNumMaturities(); _t = new double[_nCDS]; _lgd = new double[_nCDS]; _unitAccured = new double[_nCDS]; for (int i = 0; i < _nCDS; i++) { _t[i] = multiCDS.getProtectionEnd(i); _lgd[i] = multiCDS.getLGD(); _unitAccured[i] = multiCDS.getAccruedPremiumPerUnitSpread(i); } _valuationDF = Math.Exp(-yieldCurve.getRT_(multiCDS.getCashSettleTime())); //This is the global set of knots - it will be truncated down for the various leg elements //TODO this will not match ISDA C for forward starting (i.e. accStart > tradeDate) CDS, and will give different answers //if the Markit 'fix' is used in that case double[] knots = DoublesScheduleGenerator.getIntegrationsPoints( multiCDS.getEffectiveProtectionStart(), _t[_nCDS - 1], yieldCurve.t.ToArray(), _t.ToArray()); //The protection leg _protElems = new ProtectionLegElement[_nCDS]; for (int i = 0; i < _nCDS; i++) { _protElems[i] = new ProtectionLegElement( i == 0 ? multiCDS.getEffectiveProtectionStart() : _t[i - 1], _t[i], yieldCurve, i, knots); } _cds2CouponsMap = new int[_nCDS][]; _cdsCouponsUpdateMap = new int[_nCDS][]; _knot2CouponsMap = new int[_nCDS][]; List <CdsCoupon> allCoupons = new List <CdsCoupon>(_nCDS + multiCDS.getTotalPayments() - 1); allCoupons.AddRange(multiCDS.getStandardCoupons().ToList()); allCoupons.Add(multiCDS.getTerminalCoupon(_nCDS - 1)); int[] temp = new int[multiCDS.getTotalPayments()]; for (int i = 0; i < multiCDS.getTotalPayments(); i++) { temp[i] = i; } _cds2CouponsMap[_nCDS - 1] = temp; //complete the list of unique coupons and fill out the cds2CouponsMap for (int i = 0; i < _nCDS - 1; i++) { CdsCoupon c = multiCDS.getTerminalCoupon(i); int nPayments = Math.Max(0, multiCDS.getPaymentIndexForMaturity(i)) + 1; _cds2CouponsMap[i] = new int[nPayments]; for (int jj = 0; jj < nPayments - 1; jj++) { _cds2CouponsMap[i][jj] = jj; } //because of business-day adjustment, a terminal coupon can be identical to a standard coupon, //in which case it is not added again int index = allCoupons.IndexOf(c); if (index == -1) { index = allCoupons.Count; allCoupons.Add(c); } _cds2CouponsMap[i][nPayments - 1] = index; } //loop over the coupons to populate the couponUpdateMap _nCoupons = allCoupons.Count; int[] sizes = new int[_nCDS]; int[] map = new int[_nCoupons]; for (int i = 0; i < _nCoupons; i++) { CdsCoupon c = allCoupons[i]; int index = Array.BinarySearch(_t, c.getEffEnd()); if (index < 0) { index = -(index + 1); } sizes[index]++; map[i] = index; } //make the protection leg elements if (multiCDS.isPayAccOnDefault()) { _premElems = new PremiumLegElement[_nCoupons]; for (int i = 0; i < _nCoupons; i++) { _premElems[i] = new PremiumLegElement(multiCDS.getEffectiveProtectionStart(), allCoupons[i], yieldCurve, map[i], knots, formula); } } else { _premElems = new CouponOnlyElement[_nCoupons]; for (int i = 0; i < _nCoupons; i++) { _premElems[i] = new CouponOnlyElement(allCoupons[i], yieldCurve, map[i]); } } //sort a map from coupon to curve node, to a map from curve node to coupons for (int i = 0; i < _nCDS; i++) { _knot2CouponsMap[i] = new int[sizes[i]]; } int[] indexes = new int[_nCDS]; for (int i = 0; i < _nCoupons; i++) { int index = map[i]; _knot2CouponsMap[index][indexes[index]++] = i; } //the cdsCouponsUpdateMap is the intersection of the cds2CouponsMap and knot2CouponsMap for (int i = 0; i < _nCDS; i++) { _cdsCouponsUpdateMap[i] = intersection(_knot2CouponsMap[i], _cds2CouponsMap[i]); } }
public CreditCurveCalibrator(CDS[] cds, YieldTermStructure yieldCurve, AccrualOnDefaultFormulae formula) { _nCDS = cds.Length; Boolean payAccOnDefault = cds[0].isPayAccOnDefault(); double accStart = cds[0].getAccStart(); double effectProtStart = cds[0].getEffectiveProtectionStart(); double cashSettleTime = cds[0].getCashSettleTime(); _t = new double[_nCDS]; _t[0] = cds[0].getProtectionEnd(); //Check all the CDSs match for (int i = 1; i < _nCDS; i++) { _t[i] = cds[i].getProtectionEnd(); } _valuationDF = Math.Exp(-yieldCurve.getRT_(cashSettleTime)); _lgd = new double[_nCDS]; _unitAccured = new double[_nCDS]; for (int i = 0; i < _nCDS; i++) { _lgd[i] = cds[i].getLGD(); _unitAccured[i] = cds[i].getAccruedYearFraction(); } //This is the global set of knots - it will be truncated down for the various leg elements //TODO this will not match ISDA C for forward starting (i.e. accStart > tradeDate) CDS, and will give different answers //if the Markit 'fix' is used in that case double[] knots = DoublesScheduleGenerator. getIntegrationsPoints(effectProtStart, _t[_nCDS - 1], yieldCurve.t.ToArray(), _t); //The protection leg _protElems = new ProtectionLegElement[_nCDS]; for (int i = 0; i < _nCDS; i++) { _protElems[i] = new ProtectionLegElement(i == 0 ? effectProtStart : _t[i - 1], _t[i], yieldCurve, i, knots); } _cds2CouponsMap = new int[_nCDS][]; _cdsCouponsUpdateMap = new int[_nCDS][]; _knot2CouponsMap = new int[_nCDS][]; int nPaymentsFinalCDS = cds[_nCDS - 1].getNumPayments(); List <CdsCoupon> allCoupons = new List <CdsCoupon>(_nCDS + nPaymentsFinalCDS - 1); allCoupons.AddRange(cds[_nCDS - 1].getCoupons()); int[] temp = new int[nPaymentsFinalCDS]; for (int i = 0; i < nPaymentsFinalCDS; i++) { temp[i] = i; } _cds2CouponsMap[_nCDS - 1] = temp; //complete the list of unique coupons and fill out the cds2CouponsMap for (int i = 0; i < _nCDS - 1; i++) { CdsCoupon[] c = cds[i].getCoupons(); int nPayments = c.Length; _cds2CouponsMap[i] = new int[nPayments]; for (int k = 0; k < nPayments; k++) { int index = -1; for (int j = 0; j < allCoupons.Count; j++) { if (allCoupons[j].Equals(c[k])) { index = j; break; } } if (index == -1) { index = allCoupons.Count; allCoupons.Add(c[k]); } _cds2CouponsMap[i][k] = index; } } //loop over the coupons to populate the couponUpdateMap _nCoupons = allCoupons.Count; int[] sizes = new int[_nCDS]; int[] map = new int[_nCoupons]; for (int i = 0; i < _nCoupons; i++) { CdsCoupon c = allCoupons[i]; int index = Array.BinarySearch(_t, c.getEffEnd()); if (index < 0) { index = -(index + 1); } sizes[index]++; map[i] = index; } //make the protection leg elements if (payAccOnDefault) { _premElems = new PremiumLegElement[_nCoupons]; for (int i = 0; i < _nCoupons; i++) { _premElems[i] = new PremiumLegElement(effectProtStart, allCoupons[i], yieldCurve, map[i], knots, formula); } } else { _premElems = new CouponOnlyElement[_nCoupons]; for (int i = 0; i < _nCoupons; i++) { _premElems[i] = new CouponOnlyElement(allCoupons[i], yieldCurve, map[i]); } } //sort a map from coupon to curve node, to a map from curve node to coupons for (int i = 0; i < _nCDS; i++) { _knot2CouponsMap[i] = new int[sizes[i]]; } int[] indexes = new int[_nCDS]; for (int i = 0; i < _nCoupons; i++) { int index = map[i]; _knot2CouponsMap[index][indexes[index]++] = i; } //the cdsCouponsUpdateMap is the intersection of the cds2CouponsMap and knot2CouponsMap for (int i = 0; i < _nCDS; i++) { _cdsCouponsUpdateMap[i] = intersection(_knot2CouponsMap[i], _cds2CouponsMap[i]); } }
private double calculateSinglePeriodAccrualOnDefaultCreditSensitivity( CdsCoupon coupon, double effStart, double[] integrationPoints, YieldTermStructure yieldCurve, PiecewiseconstantHazardRate creditCurve, int creditCurveNode) { double start = Math.Max(coupon.getEffStart(), effStart); if (start >= coupon.getEffEnd()) { return(0.0); } double[] knots = DoublesScheduleGenerator.truncateSetInclusive(start, coupon.getEffEnd(), integrationPoints); double t = knots[0]; double ht0 = creditCurve.getRT_(t); double rt0 = yieldCurve.getRT_(t); double p0 = Math.Exp(-rt0); double q0 = Math.Exp(-ht0); double b0 = p0 * q0; // this is the risky discount factor double dqdr0 = creditCurve.getSingleNodeDiscountFactorSensitivity(t, creditCurveNode); double t0 = t - coupon.getEffStart() + _omega; double pvSense = 0.0; int nItems = knots.Length; for (int j = 1; j < nItems; ++j) { t = knots[j]; double ht1 = creditCurve.getRT_(t); double rt1 = yieldCurve.getRT_(t); double p1 = Math.Exp(-rt1); double q1 = Math.Exp(-ht1); double b1 = p1 * q1; double dqdr1 = creditCurve.getSingleNodeDiscountFactorSensitivity(t, creditCurveNode); double dt = knots[j] - knots[j - 1]; double dht = ht1 - ht0; double drt = rt1 - rt0; double dhrt = dht + drt + 1e-50; // to keep consistent with ISDA c code double tPvSense; // TODO once the maths is written up in a white paper, check these formula again, // since tests again finite difference could miss some subtle error if (_formula == AccrualOnDefaultFormulae.MARKIT_FIX) { if (Math.Abs(dhrt) < 1e-5) { double eP = Maths.Epsilon.epsilonP(-dhrt); double ePP = Maths.Epsilon.epsilonPP(-dhrt); double dPVdq0 = p0 * dt * ((1 + dht) * eP - dht * ePP); double dPVdq1 = b0 * dt / q1 * (-eP + dht * ePP); tPvSense = dPVdq0 * dqdr0 + dPVdq1 * dqdr1; } else { double w1 = (b0 - b1) / dhrt; double w2 = w1 - b1; double w3 = dht / dhrt; double w4 = dt / dhrt; double w5 = (1 - w3) * w2; double dPVdq0 = w4 / q0 * (w5 + w3 * (b0 - w1)); double dPVdq1 = w4 / q1 * (w5 + w3 * (b1 * (1 + dhrt) - w1)); tPvSense = dPVdq0 * dqdr0 - dPVdq1 * dqdr1; } } else { double t1 = t - coupon.getEffStart() + _omega; if (Math.Abs(dhrt) < 1e-5) { double e = Maths.Epsilon.epsilon(-dhrt); double eP = Maths.Epsilon.epsilonP(-dhrt); double ePP = Maths.Epsilon.epsilonPP(-dhrt); double w1 = t0 * e + dt * eP; double w2 = t0 * eP + dt * ePP; double dPVdq0 = p0 * ((1 + dht) * w1 - dht * w2); double dPVdq1 = b0 / q1 * (-w1 + dht * w2); tPvSense = dPVdq0 * dqdr0 + dPVdq1 * dqdr1; } else { double w1 = dt / dhrt; double w2 = dht / dhrt; double w3 = (t0 + w1) * b0 - (t1 + w1) * b1; double w4 = (1 - w2) / dhrt; double w5 = w1 / dhrt * (b0 - b1); double dPVdq0 = w4 * w3 / q0 + w2 * ((t0 + w1) * p0 - w5 / q0); double dPVdq1 = w4 * w3 / q1 + w2 * ((t1 + w1) * p1 - w5 / q1); tPvSense = dPVdq0 * dqdr0 - dPVdq1 * dqdr1; } t0 = t1; } pvSense += tPvSense; ht0 = ht1; rt0 = rt1; p0 = p1; q0 = q1; b0 = b1; dqdr0 = dqdr1; } return(coupon.getYFRatio() * pvSense); }
/** * The sensitivity of the PV of the protection leg to the zero rate of a given node (knot) of the yield curve. * * @param cds the analytic description of a CDS traded at a certain time * @param yieldCurve the yield (or discount) curve * @param creditCurve the credit (or survival) curve * @param yieldCurveNode the yield curve node * @return the sensitivity (on a unit notional) */ public double protectionLegYieldSensitivity( CDS cds, YieldTermStructure yieldCurve, PiecewiseconstantHazardRate creditCurve, int yieldCurveNode) { if ((yieldCurveNode != 0 && cds.getProtectionEnd() <= yieldCurve.t[yieldCurveNode - 1]) || (yieldCurveNode != creditCurve.getNumberOfKnots() - 1 && cds.getEffectiveProtectionStart() >= yieldCurve.t[yieldCurveNode + 1])) { return(0.0); // can't have any sensitivity in this case } if (cds.getProtectionEnd() <= 0.0) { //short cut already expired CDSs return(0.0); } double[] integrationSchedule = DoublesScheduleGenerator.getIntegrationsPoints( cds.getEffectiveProtectionStart(), cds.getProtectionEnd(), yieldCurve, creditCurve); double t = integrationSchedule[0]; double ht0 = creditCurve.getRT_(t); double rt0 = yieldCurve.getRT_(t); double dpdr0 = yieldCurve.getSingleNodeDiscountFactorSensitivity(t, yieldCurveNode); double q0 = Math.Exp(-ht0); double p0 = Math.Exp(-rt0); double pvSense = 0.0; int n = integrationSchedule.Length; for (int i = 1; i < n; ++i) { t = integrationSchedule[i]; double ht1 = creditCurve.getRT_(t); double dpdr1 = yieldCurve.getSingleNodeDiscountFactorSensitivity(t, yieldCurveNode); double rt1 = yieldCurve.getRT_(t); double q1 = Math.Exp(-ht1); double p1 = Math.Exp(-rt1); if (dpdr0 == 0.0 && dpdr1 == 0.0) { ht0 = ht1; rt0 = rt1; p0 = p1; q0 = q1; continue; } double hBar = ht1 - ht0; double fBar = rt1 - rt0; double fhBar = hBar + fBar; double dPVSense; double e = Maths.Epsilon.epsilon(-fhBar); double eP = Maths.Epsilon.epsilonP(-fhBar); double dPVdp0 = q0 * hBar * (e - eP); double dPVdp1 = hBar * p0 * q0 / p1 * eP; dPVSense = dPVdp0 * dpdr0 + dPVdp1 * dpdr1; pvSense += dPVSense; ht0 = ht1; dpdr0 = dpdr1; rt0 = rt1; p0 = p1; q0 = q1; } pvSense *= cds.getLGD(); // Compute the discount factor discounting the upfront payment made on the cash settlement date back to the valuation date double df = Math.Exp(-yieldCurve.getRT_(cds.getCashSettleTime())); pvSense /= df; //TODO this was put in quickly the get the right sensitivity to the first node double dfSense = yieldCurve.getSingleNodeDiscountFactorSensitivity(cds.getCashSettleTime(), yieldCurveNode); if (dfSense != 0.0) { double pro = protectionLeg(cds, yieldCurve, creditCurve); pvSense -= pro / df * dfSense; } return(pvSense); }
public double protectionLegCreditSensitivity( CDS cds, YieldTermStructure yieldCurve, PiecewiseconstantHazardRate creditCurve, int creditCurveNode) { if ((creditCurveNode != 0 && cds.getProtectionEnd() <= creditCurve.getTimeAtIndex(creditCurveNode - 1)) || (creditCurveNode != creditCurve.t.Count - 1 && cds.getEffectiveProtectionStart() >= creditCurve.getTimeAtIndex(creditCurveNode + 1))) { return(0.0); // can't have any sensitivity in this case } if (cds.getProtectionEnd() <= 0.0) { //short cut already expired CDSs return(0.0); } double[] integrationSchedule = DoublesScheduleGenerator.getIntegrationsPoints( cds.getEffectiveProtectionStart(), cds.getProtectionEnd(), yieldCurve, creditCurve); double t = integrationSchedule[0]; double ht0 = creditCurve.getRT_(t); double rt0 = yieldCurve.getRT_(t); double dqdr0 = creditCurve.getSingleNodeDiscountFactorSensitivity(t, creditCurveNode); double q0 = Math.Exp(-ht0); double p0 = Math.Exp(-rt0); double pvSense = 0.0; int n = integrationSchedule.Length; for (int i = 1; i < n; ++i) { t = integrationSchedule[i]; double ht1 = creditCurve.getRT_(t); double dqdr1 = creditCurve.getSingleNodeDiscountFactorSensitivity(t, creditCurveNode); double rt1 = yieldCurve.getRT_(t); double q1 = Math.Exp(-ht1); double p1 = Math.Exp(-rt1); if (dqdr0 == 0.0 && dqdr1 == 0.0) { ht0 = ht1; rt0 = rt1; p0 = p1; q0 = q1; continue; } double hBar = ht1 - ht0; double fBar = rt1 - rt0; double fhBar = hBar + fBar; double dPVSense; if (Math.Abs(fhBar) < 1e-5) { double e = Maths.Epsilon.epsilon(-fhBar); double eP = Maths.Epsilon.epsilonP(-fhBar); double dPVdq0 = p0 * ((1 + hBar) * e - hBar * eP); double dPVdq1 = -p0 * q0 / q1 * (e - hBar * eP); dPVSense = dPVdq0 * dqdr0 + dPVdq1 * dqdr1; } else { double w = fBar / fhBar * (p0 * q0 - p1 * q1); dPVSense = ((w / q0 + hBar * p0) / fhBar) * dqdr0 - ((w / q1 + hBar * p1) / fhBar) * dqdr1; } pvSense += dPVSense; ht0 = ht1; dqdr0 = dqdr1; rt0 = rt1; p0 = p1; q0 = q1; } pvSense *= cds.getLGD(); // Compute the discount factor discounting the upfront payment made on the cash settlement date back to the valuation date double df = Math.Exp(-yieldCurve.getRT_(cds.getCashSettleTime())); pvSense /= df; return(pvSense); }