NonstandardSwap::NonstandardSwap(const VanillaSwap &fromVanilla)
: Swap(2), type_((VanillaSwap::Type)fromVanilla.type()),
fixedNominal_(std::vector<Real>(fromVanilla.fixedLeg().size(),
fromVanilla.nominal())),
floatingNominal_(std::vector<Real>(fromVanilla.floatingLeg().size(),
fromVanilla.nominal())),
fixedSchedule_(fromVanilla.fixedSchedule()),
fixedRate_(std::vector<Real>(fromVanilla.fixedLeg().size(),
fromVanilla.fixedRate())),
fixedDayCount_(fromVanilla.fixedDayCount()),
floatingSchedule_(fromVanilla.floatingSchedule()),
iborIndex_(fromVanilla.iborIndex()),
spread_(std::vector<Real>(fromVanilla.floatingLeg().size(), fromVanilla.spread())),
gearing_(std::vector<Real>(fromVanilla.floatingLeg().size(), 1.0)),
singleSpreadAndGearing_(true),
floatingDayCount_(fromVanilla.floatingDayCount()),
paymentConvention_(fromVanilla.paymentConvention()),
intermediateCapitalExchange_(false), finalCapitalExchange_(false) {
init();
}
void BlackStyleSwaptionEngine<Spec>::calculate() const {
static const Spread basisPoint = 1.0e-4;
Date exerciseDate = arguments_.exercise->date(0);
// the part of the swap preceding exerciseDate should be truncated
// to avoid taking into account unwanted cashflows
VanillaSwap swap = *arguments_.swap;
Rate strike = swap.fixedRate();
// using the discounting curve
// swap.iborIndex() might be using a different forwarding curve
swap.setPricingEngine(boost::shared_ptr<PricingEngine>(new
DiscountingSwapEngine(discountCurve_, false)));
Rate 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()!=0.0) {
Spread correction = swap.spread() *
std::fabs(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(boost::shared_ptr<PricingEngine>(
new DiscountingSwapEngine(discountCurve_, false)));
Real annuity;
switch(arguments_.settlementType) {
case Settlement::Physical: {
annuity = std::fabs(swap.fixedLegBPS())/basisPoint;
break;
}
case Settlement::Cash: {
const Leg& fixedLeg = swap.fixedLeg();
boost::shared_ptr<FixedRateCoupon> firstCoupon =
boost::dynamic_pointer_cast<FixedRateCoupon>(fixedLeg[0]);
DayCounter dayCount = firstCoupon->dayCounter();
Real fixedLegCashBPS =
CashFlows::bps(fixedLeg,
InterestRate(atmForward, dayCount, Compounded, Annual),
false, discountCurve_->referenceDate()) ;
annuity = std::fabs(fixedLegCashBPS/basisPoint);
break;
}
default:
QL_FAIL("unknown settlement type");
}
results_.additionalResults["annuity"] = annuity;
// the swap length calculation might be improved using the value date
// of the exercise date
Time swapLength = vol_->swapLength(exerciseDate,
arguments_.floatingPayDates.back());
results_.additionalResults["swapLength"] = swapLength;
Real variance = vol_->blackVariance(exerciseDate,
swapLength,
strike);
// once the deprecated methods allowing to override the displacement
// are gone, we can avoid this and directly read the displacement
// from the volatility structure
Real displacement = displacement_ == Null<Real>()
? vol_->shift(exerciseDate, swapLength)
: displacement_;
Real stdDev = std::sqrt(variance);
results_.additionalResults["stdDev"] = stdDev;
Option::Type w = (arguments_.type==VanillaSwap::Payer) ?
Option::Call : Option::Put;
results_.value = Spec().value(w, strike, atmForward, stdDev, annuity,
displacement);
Time exerciseTime = vol_->timeFromReference(exerciseDate);
results_.additionalResults["vega"] = Spec().vega(
strike, atmForward, stdDev, exerciseTime, annuity, displacement);
}