Exemplo n.º 1
0
        public override void calculate()
        {
            Utils.QL_REQUIRE(numericalFix_ == NumericalFix.None || numericalFix_ == NumericalFix.Taylor, () =>
                             "numerical fix must be None or Taylor");
            Utils.QL_REQUIRE(accrualBias_ == AccrualBias.HalfDayBias || accrualBias_ == AccrualBias.NoBias, () =>
                             "accrual bias must be HalfDayBias or NoBias");
            Utils.QL_REQUIRE(forwardsInCouponPeriod_ == ForwardsInCouponPeriod.Flat ||
                             forwardsInCouponPeriod_ == ForwardsInCouponPeriod.Piecewise, () =>
                             "forwards in coupon period must be Flat or Piecewise");

            // it would be possible to handle the cases which are excluded below,
            // but the ISDA engine is not explicitly specified to handle them,
            // so we just forbid them too

            Actual365Fixed dc  = new Actual365Fixed();
            Actual360      dc1 = new Actual360();
            Actual360      dc2 = new Actual360(true);

            Date evalDate = Settings.Instance.evaluationDate();

            // check if given curves are ISDA compatible
            // (the interpolation is checked below)

            Utils.QL_REQUIRE(!discountCurve_.empty(), () => "no discount term structure set");
            Utils.QL_REQUIRE(!probability_.empty(), () => "no probability term structure set");
            Utils.QL_REQUIRE(discountCurve_.link.dayCounter() == dc, () =>
                             "yield term structure day counter (" + discountCurve_.link.dayCounter() + ") should be Act/365(Fixed)");
            Utils.QL_REQUIRE(probability_.link.dayCounter() == dc, () =>
                             "probability term structure day counter (" + probability_.link.dayCounter() + ") should be "
                             + "Act/365(Fixed)");
            Utils.QL_REQUIRE(discountCurve_.link.referenceDate() == evalDate, () =>
                             "yield term structure reference date (" + discountCurve_.link.referenceDate()
                             + " should be evaluation date (" + evalDate + ")");
            Utils.QL_REQUIRE(probability_.link.referenceDate() == evalDate, () =>
                             "probability term structure reference date (" + probability_.link.referenceDate()
                             + " should be evaluation date (" + evalDate + ")");
            Utils.QL_REQUIRE(arguments_.settlesAccrual, () => "ISDA engine not compatible with non accrual paying CDS");
            Utils.QL_REQUIRE(arguments_.paysAtDefaultTime, () => "ISDA engine not compatible with end period payment");
            Utils.QL_REQUIRE((arguments_.claim as FaceValueClaim) != null, () =>
                             "ISDA engine not compatible with non face value claim");

            Date maturity = arguments_.maturity;
            Date effectiveProtectionStart = Date.Max(arguments_.protectionStart, evalDate + 1);

            // collect nodes from both curves and sort them
            List <Date> yDates = new List <Date>(), cDates = new List <Date>();

            var castY1 = discountCurve_.link as PiecewiseYieldCurve <Discount, LogLinear>;
            var castY2 = discountCurve_.link as InterpolatedForwardCurve <BackwardFlat>;
            var castY3 = discountCurve_.link as InterpolatedForwardCurve <ForwardFlat>;
            var castY4 = discountCurve_.link as FlatForward;

            if (castY1 != null)
            {
                if (castY1.dates() != null)
                {
                    yDates = castY1.dates();
                }
            }
            else if (castY2 != null)
            {
                yDates = castY2.dates();
            }
            else if (castY3 != null)
            {
                yDates = castY3.dates();
            }
            else if (castY4 != null)
            {
            }
            else
            {
                Utils.QL_FAIL("Yield curve must be flat forward interpolated");
            }

            var castC1 = probability_.link as InterpolatedSurvivalProbabilityCurve <LogLinear>;
            var castC2 = probability_.link as InterpolatedHazardRateCurve <BackwardFlat>;
            var castC3 = probability_.link as FlatHazardRate;

            if (castC1 != null)
            {
                cDates = castC1.dates();
            }
            else if (castC2 != null)
            {
                cDates = castC2.dates();
            }
            else if (castC3 != null)
            {
            }
            else
            {
                Utils.QL_FAIL("Credit curve must be flat forward interpolated");
            }

            // Todo check
            List <Date> nodes = yDates.Union(cDates).ToList();

            if (nodes.empty())
            {
                nodes.Add(maturity);
            }
            double nFix = (numericalFix_ == NumericalFix.None ? 1E-50 : 0.0);

            // protection leg pricing (npv is always negative at this stage)
            double protectionNpv = 0.0;

            Date   d0 = effectiveProtectionStart - 1;
            double P0 = discountCurve_.link.discount(d0);
            double Q0 = probability_.link.survivalProbability(d0);
            Date   d1;
            int    result = nodes.FindIndex(item => item > effectiveProtectionStart);

            for (int it = result; it < nodes.Count; ++it)
            {
                if (nodes[it] > maturity)
                {
                    d1 = maturity;
                    it = nodes.Count - 1; //early exit
                }
                else
                {
                    d1 = nodes[it];
                }
                double P1 = discountCurve_.link.discount(d1);
                double Q1 = probability_.link.survivalProbability(d1);

                double fhat  = Math.Log(P0) - Math.Log(P1);
                double hhat  = Math.Log(Q0) - Math.Log(Q1);
                double fhphh = fhat + hhat;

                if (fhphh < 1E-4 && numericalFix_ == NumericalFix.Taylor)
                {
                    double fhphhq = fhphh * fhphh;
                    protectionNpv +=
                        P0 * Q0 * hhat * (1.0 - 0.5 * fhphh + 1.0 / 6.0 * fhphhq -
                                          1.0 / 24.0 * fhphhq * fhphh +
                                          1.0 / 120 * fhphhq * fhphhq);
                }
                else
                {
                    protectionNpv += hhat / (fhphh + nFix) * (P0 * Q0 - P1 * Q1);
                }
                d0 = d1;
                P0 = P1;
                Q0 = Q1;
            }
            protectionNpv *= arguments_.claim.amount(null, arguments_.notional.Value, recoveryRate_);

            results_.defaultLegNPV = protectionNpv;

            // premium leg pricing (npv is always positive at this stage)

            double premiumNpv = 0.0, defaultAccrualNpv = 0.0;
            double?accruedAmount = null;

            for (int i = 0; i < arguments_.leg.Count; ++i)
            {
                FixedRateCoupon coupon = arguments_.leg[i] as FixedRateCoupon;

                Utils.QL_REQUIRE(coupon.dayCounter() == dc ||
                                 coupon.dayCounter() == dc1 ||
                                 coupon.dayCounter() == dc2, () =>
                                 "ISDA engine requires a coupon day counter Act/365Fixed "
                                 + "or Act/360 (" + coupon.dayCounter() + ")");

                // premium coupons

                if (!arguments_.leg[i].hasOccurred(evalDate, includeSettlementDateFlows_))
                {
                    double x1 = coupon.amount();
                    double x2 = discountCurve_.link.discount(coupon.date());
                    double x3 = probability_.link.survivalProbability(coupon.date() - 1);

                    // accrual
                    if (accruedAmount == null)
                    {
                        if (evalDate + 1 == coupon.date())
                        {
                            accruedAmount = 0.0;
                            premiumNpv   -= coupon.accruedPeriod(evalDate + 1) *
                                            coupon.nominal() *
                                            coupon.rate();
                        }
                        else
                        {
                            accruedAmount = coupon.accruedPeriod(evalDate + 1) *
                                            coupon.nominal() *
                                            coupon.rate();
                        }
                    }

                    premiumNpv += x1 * x2 * x3;
                }

                // default accruals

                if (!new simple_event(coupon.accrualEndDate())
                    .hasOccurred(effectiveProtectionStart, false))
                {
                    Date   start  = Date.Max(coupon.accrualStartDate(), effectiveProtectionStart) - 1;
                    Date   end    = coupon.date() - 1;
                    double tstart = discountCurve_.link.timeFromReference(coupon.accrualStartDate() - 1) -
                                    (accrualBias_ == AccrualBias.HalfDayBias ? 1.0 / 730.0 : 0.0);
                    List <Date> localNodes = new List <Date>();
                    localNodes.Add(start);
                    //add intermediary nodes, if any
                    if (forwardsInCouponPeriod_ == ForwardsInCouponPeriod.Piecewise)
                    {
                        foreach (Date node in nodes)
                        {
                            if (node > start && node < end)
                            {
                                localNodes.Add(node);
                            }
                        }
                        //std::vector<Date>::const_iterator it0 = std::upper_bound(nodes.begin(), nodes.end(), start);
                        //std::vector<Date>::const_iterator it1 = std::lower_bound(nodes.begin(), nodes.end(), end);
                        //localNodes.insert(localNodes.end(), it0, it1);
                    }
                    localNodes.Add(end);

                    double defaultAccrThisNode = 0.0;
                    Date   firstnode           = localNodes.First();
                    double t0 = discountCurve_.link.timeFromReference(firstnode);
                    P0 = discountCurve_.link.discount(firstnode);
                    Q0 = probability_.link.survivalProbability(firstnode);

                    foreach (Date node in localNodes.Skip(1)) //for (++node; node != localNodes.Last(); ++node)
                    {
                        double t1    = discountCurve_.link.timeFromReference(node);
                        double P1    = discountCurve_.link.discount(node);
                        double Q1    = probability_.link.survivalProbability(node);
                        double fhat  = Math.Log(P0) - Math.Log(P1);
                        double hhat  = Math.Log(Q0) - Math.Log(Q1);
                        double fhphh = fhat + hhat;
                        if (fhphh < 1E-4 && numericalFix_ == NumericalFix.Taylor)
                        {
                            // see above, terms up to (f+h)^3 seem more than enough,
                            // what exactly is implemented in the standard isda C
                            // code ?
                            double fhphhq = fhphh * fhphh;
                            defaultAccrThisNode +=
                                hhat * P0 * Q0 *
                                ((t0 - tstart) *
                                 (1.0 - 0.5 * fhphh + 1.0 / 6.0 * fhphhq -
                                  1.0 / 24.0 * fhphhq * fhphh) +
                                 (t1 - t0) *
                                 (0.5 - 1.0 / 3.0 * fhphh + 1.0 / 8.0 * fhphhq -
                                  1.0 / 30.0 * fhphhq * fhphh));
                        }
                        else
                        {
                            defaultAccrThisNode +=
                                (hhat / (fhphh + nFix)) *
                                ((t1 - t0) * ((P0 * Q0 - P1 * Q1) / (fhphh + nFix) -
                                              P1 * Q1) +
                                 (t0 - tstart) * (P0 * Q0 - P1 * Q1));
                        }

                        t0 = t1;
                        P0 = P1;
                        Q0 = Q1;
                    }
                    defaultAccrualNpv += defaultAccrThisNode * arguments_.notional.Value *
                                         coupon.rate() * 365.0 / 360.0;
                }
            }

            results_.couponLegNPV     = premiumNpv + defaultAccrualNpv;
            results_.accruedAmountNPV = accruedAmount;

            // upfront flow npv

            double upfPVO1 = 0.0;

            results_.upfrontNPV = 0.0;
            if (!arguments_.upfrontPayment.hasOccurred(
                    evalDate, includeSettlementDateFlows_))
            {
                upfPVO1 =
                    discountCurve_.link.discount(arguments_.upfrontPayment.date());
                if (arguments_.upfrontPayment.amount().IsNotEqual(0.0))
                {
                    results_.upfrontNPV = upfPVO1 * arguments_.upfrontPayment.amount();
                }
            }

            results_.accrualRebateNPV = 0.0;
            if (arguments_.accrualRebate != null &&
                arguments_.accrualRebate.amount().IsNotEqual(0.0) &&
                !arguments_.accrualRebate.hasOccurred(evalDate, includeSettlementDateFlows_))
            {
                results_.accrualRebateNPV =
                    discountCurve_.link.discount(arguments_.accrualRebate.date()) *
                    arguments_.accrualRebate.amount();
            }

            double upfrontSign = 1;

            if (arguments_.side == CreditDefaultSwap.Protection.Side.Seller)
            {
                results_.defaultLegNPV    *= -1.0;
                results_.accrualRebateNPV *= -1.0;
                results_.accruedAmountNPV *= -1.0;
            }
            else
            {
                results_.couponLegNPV *= -1.0;
                results_.upfrontNPV   *= -1.0;
            }

            results_.value = results_.defaultLegNPV + results_.couponLegNPV +
                             results_.upfrontNPV + results_.accrualRebateNPV;

            results_.errorEstimate = null;

            if (results_.couponLegNPV.IsNotEqual(0.0))
            {
                results_.fairSpread =
                    -results_.defaultLegNPV * arguments_.spread /
                    (results_.couponLegNPV + results_.accruedAmountNPV + results_.accrualRebateNPV);
            }
            else
            {
                results_.fairSpread = null;
            }

            double upfrontSensitivity = upfPVO1 * arguments_.notional.Value;

            if (upfrontSensitivity.IsNotEqual(0.0))
            {
                results_.fairUpfront =
                    -upfrontSign * (results_.defaultLegNPV + results_.couponLegNPV +
                                    results_.accrualRebateNPV) /
                    upfrontSensitivity;
            }
            else
            {
                results_.fairUpfront = null;
            }

            if (arguments_.spread.IsNotEqual(0.0))
            {
                results_.couponLegBPS =
                    results_.couponLegNPV * Const.BASIS_POINT / arguments_.spread;
            }
            else
            {
                results_.couponLegBPS = null;
            }

            if (arguments_.upfront != null && arguments_.upfront.IsNotEqual(0.0))
            {
                results_.upfrontBPS =
                    results_.upfrontNPV * Const.BASIS_POINT / arguments_.upfront;
            }
            else
            {
                results_.upfrontBPS = null;
            }
        }
Exemplo n.º 2
0
        public CommercialPaper(Type type, double nominal,
                               Schedule fixedSchedule, double fixedRate, DayCounter fixedDayCount,
                               Schedule principalSchedule, BusinessDayConvention?paymentConvention) :
            base(2)
        {
            type_              = type;
            nominal_           = nominal;
            fixedSchedule_     = fixedSchedule;
            fixedRate_         = fixedRate;
            fixedDayCount_     = fixedDayCount;
            principalSchedule_ = principalSchedule;

            if (paymentConvention.HasValue)
            {
                paymentConvention_ = paymentConvention.Value;
            }
            else
            {
                paymentConvention_ = fixedSchedule_.businessDayConvention();
            }

            List <CashFlow> principalLeg = new PricipalLeg(principalSchedule, fixedDayCount)
                                           .withNotionals(nominal)
                                           .withPaymentAdjustment(paymentConvention_)
                                           .withSign(type == Type.Loan ? -1 : 1);

            // temporary
            for (int i = 0; i < principalLeg.Count - 1; i++)
            {
                Principal p = (Principal)principalLeg[i];
                notionals_.Add(p.nominal());
            }

            List <CashFlow> fixedLeg = new FixedRateLeg(fixedSchedule)
                                       .withCouponRates(fixedRate, fixedDayCount)
                                       .withPaymentAdjustment(paymentConvention_)
                                       .withNotionals(notionals_);

            // Discounting Pricipal
            notionals_.Clear();
            double n;

            for (int i = 0; i < fixedLeg.Count; i++)
            {
                FixedRateCoupon c = (FixedRateCoupon)fixedLeg[i];
                n = i > 0 ? notionals_.Last() : c.nominal();
                notionals_.Add(n / (1 + (c.rate() * c.dayCounter().yearFraction(c.referencePeriodStart, c.referencePeriodEnd))));
            }

            // New Leg
            List <CashFlow> discountedFixedLeg = new FixedRateLeg(fixedSchedule)
                                                 .withCouponRates(fixedRate, fixedDayCount)
                                                 .withPaymentAdjustment(paymentConvention_)
                                                 .withNotionals(notionals_);
            // Adjust Principal
            Principal p0 = (Principal)principalLeg[0];

            p0.setAmount(notionals_.Last());

            legs_[0] = discountedFixedLeg;
            legs_[1] = principalLeg;
            if (type_ == Type.Loan)
            {
                payer_[0] = +1;
                payer_[1] = -1;
            }
            else
            {
                payer_[0] = -1;
                payer_[1] = +1;
            }
        }