double LmmVanillaSwapPricer::pvFixedLeg(
const LMM::Index indexValuationDate,
const VanillaSwap & vanillaSwap,
const std::vector<double> & numeraire) const
{
assert(indexValuationDate <= vanillaSwap.get_indexStart()); //YY TODO: this test too slow, esp: within MC simulation
assert(pLMMTenorStructure_->get_horizon() >= vanillaSwap.get_indexEnd()); // if not cannot price this swap;
const double calculatedAnuity = this->annuity(indexValuationDate,vanillaSwap,numeraire);
return vanillaSwap.get_strike()*calculatedAnuity;
}
double LmmVanillaSwapPricer::swapNPV_Analytical_1(const VanillaSwap& vanillaSwap, const std::vector<double>& liborsInitValue) const // initLibor[i] = L_i[T_0]
{
assert(pLMMTenorStructure_->get_horizon()+1 == liborsInitValue.size());
assert(pLMMTenorStructure_->get_horizon() >= vanillaSwap.get_indexEnd()); // if not cannot price this swap;
size_t horizon = pLMMTenorStructure_->get_horizon();
const double & floatingLegdelta_T = vanillaSwap.get_floatingLegTenorType().YearFraction();
const double & fixedLegdelta_T = vanillaSwap.get_fixedLegTenorType().YearFraction();
//! ZC[i] = P(T_0,T_i)
std::vector<double> ZC(horizon+2);
ZC[0] = 1.0;
for(size_t i=1; i<ZC.size(); ++i)
{
ZC[i] = ZC[i-1]/(1+floatingLegdelta_T*liborsInitValue[i-1]);
}
//! pvFloatingLeg: 1 - 1
const std::vector<LMM::Index>& floatingLegPaymentIndexSchedule = vanillaSwap.get_floatingLegPaymentIndexSchedule();
//size_t floatingLegTenorLmmTenorRatio = vanillaSwap.get_floatingLegTenorLmmTenorRatio();
LMM::Index indexFloatingLegStart = floatingLegPaymentIndexSchedule.front();
LMM::Index indexFloatingLegEnd = floatingLegPaymentIndexSchedule.back();
double pvFloatingLeg = ZC[indexFloatingLegStart-1] - ZC[indexFloatingLegEnd];
////! pvFloatingLeg: exact
//double pvFloatingLeg = 0.0;
//const std::vector<LMM::Index>& floatingLegPaymentIndexSchedule = vanillaSwap.get_floatingLegPaymentIndexSchedule();
//for(size_t itr = 0; itr < floatingLegPaymentIndexSchedule.size(); ++itr)
//{
// //! At time T_{i+1}, pay: L_i(T_i)
// size_t floatingLegPaymentIndex = floatingLegPaymentIndexSchedule[itr]; // = i+1
// size_t indexLibor = floatingLegPaymentIndex-1; // =i, because : floatingTenor = lmmTenor
// pvFloatingLeg += floatingLegdelta_T*initLibor[indexLibor]*ZC[floatingLegPaymentIndex];
//}
//! pvFixedLeg
double pvFixedLeg = 0.0;
const std::vector<LMM::Index>& fixedLegPaymentIndexSchedule = vanillaSwap.get_fixedLegPaymentIndexSchedule();
for(size_t itr = 0; itr < fixedLegPaymentIndexSchedule.size(); ++itr)
{
size_t fixedLegPaymentIndex = fixedLegPaymentIndexSchedule[itr]; // = itr+1
pvFixedLeg += fixedLegdelta_T*ZC[fixedLegPaymentIndex];
}
pvFixedLeg *= vanillaSwap.get_strike();
return pvFloatingLeg - pvFixedLeg;
}