/**
* Calculates the present value of the swaption product.
*
* <p>The result is expressed using the currency of the swapion.
*
* @param swaption the product to price
* @param ratesProvider the rates provider
* @param volatilityProvider the normal volatility provider
* @return the present value of the swaption product
*/
public CurrencyAmount presentValue(
SwaptionProduct swaption,
RatesProvider ratesProvider,
NormalVolatilitySwaptionProvider volatilityProvider) {
ExpandedSwaption expanded = swaption.expand();
validate(ratesProvider, expanded, volatilityProvider);
ZonedDateTime expiryDateTime = expanded.getExpiryDateTime();
double expiry = volatilityProvider.relativeTime(expiryDateTime);
ExpandedSwap underlying = expanded.getUnderlying();
ExpandedSwapLeg fixedLeg = fixedLeg(underlying);
if (expiry < 0.0d) { // Option has expired already
return CurrencyAmount.of(fixedLeg.getCurrency(), 0.0d);
}
double forward = swapPricer.parRate(underlying, ratesProvider);
double pvbp = swapPricer.getLegPricer().pvbp(fixedLeg, ratesProvider);
double strike = swapPricer.getLegPricer().couponEquivalent(fixedLeg, ratesProvider, pvbp);
double tenor = volatilityProvider.tenor(fixedLeg.getStartDate(), fixedLeg.getEndDate());
double volatility = volatilityProvider.getVolatility(expiryDateTime, tenor, strike, forward);
NormalFunctionData normalData = NormalFunctionData.of(forward, Math.abs(pvbp), volatility);
boolean isCall = (fixedLeg.getPayReceive() == PayReceive.PAY);
// Payer at strike is exercise when rate > strike, i.e. call on rate
EuropeanVanillaOption option =
EuropeanVanillaOption.of(strike, expiry, isCall ? PutCall.CALL : PutCall.PUT);
// option required to pass the strike (in case the swap has non-constant coupon).
Function1D<NormalFunctionData, Double> func = NORMAL.getPriceFunction(option);
double pv =
func.evaluate(normalData) * ((expanded.getLongShort() == LongShort.LONG) ? 1.0 : -1.0);
return CurrencyAmount.of(fixedLeg.getCurrency(), pv);
}
