inline boost::shared_ptr<LongstaffSchwartzMultiPathPricer>
MCAmericanPathEngine<RNG>::lsmPathPricer() const {
boost::shared_ptr<StochasticProcessArray> processArray =
boost::dynamic_pointer_cast<StochasticProcessArray>(this->process_);
QL_REQUIRE(processArray && processArray->size()>0,
"Stochastic process array required");
boost::shared_ptr<GeneralizedBlackScholesProcess> process =
boost::dynamic_pointer_cast<GeneralizedBlackScholesProcess>(
processArray->process(0));
QL_REQUIRE(process, "generalized Black-Scholes process required");
const TimeGrid theTimeGrid = this->timeGrid();
const std::vector<Time> & times = theTimeGrid.mandatoryTimes();
const Size numberOfTimes = times.size();
const std::vector<Date> & fixings = this->arguments_.fixingDates;
QL_REQUIRE(fixings.size() == numberOfTimes, "Invalid dates/times");
std::vector<Size> timePositions(numberOfTimes);
Array discountFactors(numberOfTimes);
std::vector<Handle<YieldTermStructure> > forwardTermStructures(numberOfTimes);
const Handle<YieldTermStructure> & riskFreeRate = process->riskFreeRate();
for (Size i = 0; i < numberOfTimes; ++i) {
timePositions[i] = theTimeGrid.index(times[i]);
discountFactors[i] = riskFreeRate->discount(times[i]);
forwardTermStructures[i] = Handle<YieldTermStructure>(
boost::make_shared<ImpliedTermStructure>(riskFreeRate,
fixings[i]));
}
const Size polynomialOrder = 2;
const LsmBasisSystem::PolynomType polynomType = LsmBasisSystem::Monomial;
return boost::shared_ptr<LongstaffSchwartzMultiPathPricer> (
new LongstaffSchwartzMultiPathPricer(this->arguments_.payoff,
timePositions,
forwardTermStructures,
discountFactors,
polynomialOrder,
polynomType));
}
inline
boost::shared_ptr<typename MCPathBasketEngine<RNG,S>::path_pricer_type>
MCPathBasketEngine<RNG,S>::pathPricer() const {
boost::shared_ptr<PathPayoff> payoff = arguments_.payoff;
QL_REQUIRE(payoff, "non-basket payoff given");
boost::shared_ptr<GeneralizedBlackScholesProcess> process =
boost::dynamic_pointer_cast<GeneralizedBlackScholesProcess>(
process_->process(0));
QL_REQUIRE(process, "Black-Scholes process required");
const TimeGrid theTimeGrid = timeGrid();
const std::vector<Time> & times = theTimeGrid.mandatoryTimes();
const Size numberOfTimes = times.size();
const std::vector<Date> & fixings = this->arguments_.fixingDates;
QL_REQUIRE(fixings.size() == numberOfTimes, "Invalid dates/times");
std::vector<Size> timePositions(numberOfTimes);
Array discountFactors(numberOfTimes);
std::vector<Handle<YieldTermStructure> > forwardTermStructures(numberOfTimes);
const Handle<YieldTermStructure> & riskFreeRate = process->riskFreeRate();
for (Size i = 0; i < numberOfTimes; ++i) {
timePositions[i] = theTimeGrid.index(times[i]);
discountFactors[i] = riskFreeRate->discount(times[i]);
forwardTermStructures[i] = Handle<YieldTermStructure>(
new ImpliedTermStructure(riskFreeRate, fixings[i]));
}
return boost::shared_ptr<
typename MCPathBasketEngine<RNG,S>::path_pricer_type>(
new EuropeanPathMultiPathPricer(payoff, timePositions,
forwardTermStructures,
discountFactors));
}
//! \brief Calculate the NPV of the remaining cash flow at default time \f$ \tau \f$.
//!
//! The calculation method used here is based on CIR model.
virtual Real defaultNPV(const MultiPath& path, Time defaultTime) const {
//find short rate at default time
TimeGrid timeGrid = path[0].timeGrid();
auto defaultPos = timeGrid.index(defaultTime);
Real shortRate = path[0][defaultPos];
//calculate discount factor from reference time to the default time
Time previousTime = timeGrid[0];
Real discountFactor = 1.0;
for (auto i = 0; i <= defaultPos; ++i){
discountFactor *= std::exp(-path[0].value(i) * (timeGrid[i] - previousTime));
previousTime = timeGrid[i];
}
boost::shared_ptr<const MCVanillaSwapUCVAEngine> engine = engine_.lock();
VanillaSwap::arguments* arguments = dynamic_cast<VanillaSwap::arguments*>(engine->getArguments());
Handle<YieldTermStructure> discountCurve = engine->discountCurve();
Date referenceDate = discountCurve->referenceDate();
std::vector<Date> fixedDates = arguments->fixedPayDates;
std::vector<Date> floatingDates = arguments->floatingPayDates;
// transfer payment Dates to Times
std::vector<Real> fixedTimes;
std::vector<Real> floatingTimes;
for (int i = 0; i != fixedDates.size(); ++i){
fixedTimes.push_back(engine->instrument()->fixedDayCount().yearFraction(referenceDate, fixedDates[i]));
}
for (int i = 0; i != floatingDates.size(); ++i){
floatingTimes.push_back(engine->instrument()->floatingDayCount().yearFraction(referenceDate, floatingDates[i]));
}
// calculate the corresponding discount factors of each leg to default time
std::vector<Real> fixedDiscountFactor;
std::vector<Real> floatingDiscountFactor;
int fixedIndex = 0;
int floatingIndex = 0;
for (int i = 0; i != fixedTimes.size(); ++i){
if (fixedTimes[i] >= defaultTime){
fixedDiscountFactor.push_back(engine->Model()->discountBond(0.0, fixedTimes[i] - defaultTime, shortRate));
}
else{
++fixedIndex;
}
}
for (int i = 0; i != floatingTimes.size(); ++i){
if (floatingTimes[i] >= defaultTime){
floatingDiscountFactor.push_back(engine->Model()->discountBond(0.0, floatingTimes[i] - defaultTime, shortRate));
}
else{
++floatingIndex;
}
}
//calculate the NPV(tau)
Real NPVtau = 0.0;
NPVtau += arguments->nominal * (1. - floatingDiscountFactor.back());
for (int m = 0; m != floatingDiscountFactor.size(); ++m){
NPVtau += arguments->nominal * arguments->floatingSpreads[m + floatingIndex] * floatingDiscountFactor[m];
}
for (int m = 0; m != fixedDiscountFactor.size(); ++m){
NPVtau -= arguments->fixedCoupons[m + fixedIndex] * fixedDiscountFactor[m];
}
if (arguments->type == QuantLib::VanillaSwap::Payer){
NPVtau = NPVtau;
}
else{
NPVtau = -NPVtau;
}
return NPVtau * discountFactor;
}
boost::shared_ptr<IRDLSCallablePricer>
MCIRDLSLSEngine::lsmPathPricer() const {
boost::shared_ptr<StochasticProcessArray> processArray =
boost::dynamic_pointer_cast<StochasticProcessArray>(this->process_);
QL_REQUIRE(processArray && processArray->size()>0,
"Stochastic process array required");
boost::shared_ptr<PayoffLeg> payoffLeg = arguments_.payoffLeg;
QL_REQUIRE(payoffLeg, "IRDLS payoffLeg given");
//const Handle<YieldTermStructure> &df=arguments_.df;
//Frequency freq = arguments_.freq;
const TimeGrid theTimeGrid = this->timeGrid();
const std::vector<Time> & times = theTimeGrid.mandatoryTimes();
const Size numberOfTimes = times.size();
const std::vector<Date> & fixings = this->arguments_.fixingDates;
std::vector<Date> remainfixings;
Date today = Settings::instance().evaluationDate();
const Size numberOfFixings = fixings.size();
for(Size i=0;i<numberOfFixings;++i){
if(fixings[i]>today){
remainfixings.push_back(fixings[i]);
}
}
const Size numberOfRemainFixings = remainfixings.size();
additionalStats_.resize(numberOfTimes);
QL_REQUIRE(numberOfRemainFixings == numberOfTimes, "Invalid dates/times");
std::vector<Size> timePositions(numberOfTimes);
Array discountFactors(numberOfTimes);
//std::vector<Handle<YieldTermStructure> > forwardTermStructures(numberOfTimes);
//const Handle<YieldTermStructure> & riskFreeRate = process->riskFreeRate();
for (Size i = 0; i < numberOfTimes; ++i){
timePositions[i] = theTimeGrid.index(times[i]);
discountFactors[i] = discountTS_->discount(times[i]);
}
// forwardTermStructures[i] = Handle<YieldTermStructure>(
// new ImpliedTermStructure(riskFreeRate, fixings[i]));
const Size polynomialOrder = 2;
const LsmBasisSystem::PolynomType polynomType = LsmBasisSystem::Monomial;
return boost::shared_ptr<IRDLSCallablePricer> (
new IRDLSCallablePricer(payoffLeg,
timePositions,
process_,
discountFactors,
additionalStats_,
polynomialOrder,
polynomType));
}
