public GFunctionExactYield(CmsCoupon coupon)
{
SwapIndex swapIndex = coupon.swapIndex();
VanillaSwap swap = swapIndex.underlyingSwap(coupon.fixingDate());
Schedule schedule = swap.fixedSchedule();
Handle <YieldTermStructure> rateCurve = swapIndex.forwardingTermStructure();
DayCounter dc = swapIndex.dayCounter();
double swapStartTime = dc.yearFraction(rateCurve.link.referenceDate(), schedule.startDate());
double swapFirstPaymentTime = dc.yearFraction(rateCurve.link.referenceDate(), schedule.date(1));
double paymentTime = dc.yearFraction(rateCurve.link.referenceDate(), coupon.date());
delta_ = (paymentTime - swapStartTime) / (swapFirstPaymentTime - swapStartTime);
List <CashFlow> fixedLeg = new List <CashFlow>(swap.fixedLeg());
int n = fixedLeg.Count;
accruals_ = new List <double>();
for (int i = 0; i < n; ++i)
{
Coupon coupon1 = fixedLeg[i] as Coupon;
accruals_.Add(coupon1.accrualPeriod());
}
}
//===========================================================================//
// GFunctionWithShifts //
//===========================================================================//
public GFunctionWithShifts(CmsCoupon coupon, Handle <Quote> meanReversion)
{
meanReversion_ = meanReversion;
calibratedShift_ = 0.03;
tmpRs_ = 10000000.0;
accuracy_ = 1.0e-14;
SwapIndex swapIndex = coupon.swapIndex();
VanillaSwap swap = swapIndex.underlyingSwap(coupon.fixingDate());
swapRateValue_ = swap.fairRate();
objectiveFunction_ = new ObjectiveFunction(this, swapRateValue_);
Schedule schedule = swap.fixedSchedule();
Handle <YieldTermStructure> rateCurve = swapIndex.forwardingTermStructure();
DayCounter dc = swapIndex.dayCounter();
swapStartTime_ = dc.yearFraction(rateCurve.link.referenceDate(), schedule.startDate());
discountAtStart_ = rateCurve.link.discount(schedule.startDate());
double paymentTime = dc.yearFraction(rateCurve.link.referenceDate(), coupon.date());
shapedPaymentTime_ = shapeOfShift(paymentTime);
List <CashFlow> fixedLeg = new List <CashFlow>(swap.fixedLeg());
int n = fixedLeg.Count;
shapedSwapPaymentTimes_ = new List <double>();
swapPaymentDiscounts_ = new List <double>();
accruals_ = new List <double>();
for (int i = 0; i < n; ++i)
{
Coupon coupon1 = fixedLeg[i] as Coupon;
accruals_.Add(coupon1.accrualPeriod());
Date paymentDate = new Date(coupon1.date().serialNumber());
double swapPaymentTime = dc.yearFraction(rateCurve.link.referenceDate(), paymentDate);
shapedSwapPaymentTimes_.Add(shapeOfShift(swapPaymentTime));
swapPaymentDiscounts_.Add(rateCurve.link.discount(paymentDate));
}
discountRatio_ = swapPaymentDiscounts_.Last() / discountAtStart_;
}
public override void calculate()
{
Date exerciseDate = arguments_.exercise.date(0);
// the part of the swap preceding exerciseDate should be truncated
// to avoid taking into account unwanted cashflows
// for the moment we add a check avoiding this situation
VanillaSwap swap = arguments_.swap;
double strike = swap.fixedRate;
List <CashFlow> fixedLeg = swap.fixedLeg();
FixedRateCoupon firstCoupon = fixedLeg[0] as FixedRateCoupon;
Utils.QL_REQUIRE(firstCoupon != null, () => "wrong coupon type");
Utils.QL_REQUIRE(firstCoupon.accrualStartDate() >= exerciseDate,
() => "swap start (" + firstCoupon.accrualStartDate() + ") before exercise date ("
+ exerciseDate + ") not supported in Black swaption engine");
// using the forecasting curve
swap.setPricingEngine(new DiscountingSwapEngine(swap.iborIndex().forwardingTermStructure()));
double atmForward = swap.fairRate();
// Volatilities are quoted for zero-spreaded swaps.
// Therefore, any spread on the floating leg must be removed
// with a corresponding correction on the fixed leg.
if (swap.spread.IsNotEqual(0.0))
{
double correction = swap.spread * Math.Abs(swap.floatingLegBPS() / swap.fixedLegBPS());
strike -= correction;
atmForward -= correction;
results_.additionalResults["spreadCorrection"] = correction;
}
else
{
results_.additionalResults["spreadCorrection"] = 0.0;
}
results_.additionalResults["strike"] = strike;
results_.additionalResults["atmForward"] = atmForward;
// using the discounting curve
swap.setPricingEngine(new DiscountingSwapEngine(discountCurve_, false));
double annuity = 0;
if (arguments_.settlementType == Settlement.Type.Physical ||
(arguments_.settlementType == Settlement.Type.Cash &&
arguments_.settlementMethod == Settlement.Method.CollateralizedCashPrice))
{
annuity = Math.Abs(swap.fixedLegBPS()) / Const.BASIS_POINT;
}
else if (arguments_.settlementType == Settlement.Type.Cash &&
arguments_.settlementMethod == Settlement.Method.ParYieldCurve)
{
DayCounter dayCount = firstCoupon.dayCounter();
// we assume that the cash settlement date is equal
// to the swap start date
Date discountDate = model_ == CashAnnuityModel.DiscountCurve
? firstCoupon.accrualStartDate()
: discountCurve_.link.referenceDate();
double fixedLegCashBPS =
CashFlows.bps(fixedLeg,
new InterestRate(atmForward, dayCount, Compounding.Compounded, Frequency.Annual), false,
discountDate);
annuity = Math.Abs(fixedLegCashBPS / Const.BASIS_POINT) * discountCurve_.link.discount(discountDate);
}
else
{
Utils.QL_FAIL("unknown settlement type");
}
results_.additionalResults["annuity"] = annuity;
double swapLength = vol_.link.swapLength(swap.floatingSchedule().dates().First(),
swap.floatingSchedule().dates().Last());
results_.additionalResults["swapLength"] = swapLength;
double variance = vol_.link.blackVariance(exerciseDate,
swapLength,
strike);
double displacement = displacement_ == null
? vol_.link.shift(exerciseDate, swapLength)
: Convert.ToDouble(displacement_);
double stdDev = Math.Sqrt(variance);
results_.additionalResults["stdDev"] = stdDev;
Option.Type w = (arguments_.type == VanillaSwap.Type.Payer) ? Option.Type.Call : Option.Type.Put;
results_.value = new Spec().value(w, strike, atmForward, stdDev, annuity, displacement);
double exerciseTime = vol_.link.timeFromReference(exerciseDate);
results_.additionalResults["vega"] =
new Spec().vega(strike, atmForward, stdDev, exerciseTime, annuity, displacement);
}