final double strikeModified = METHOD_SWAP.couponEquivalent(swaption.getUnderlyingSwap(), pvbpModified, sabrData.getMulticurveProvider());
final double maturity = swaption.getMaturityTime();
// TODO: A better notion of maturity may be required (using period?)
final EuropeanVanillaOption option = new EuropeanVanillaOption(strikeModified, swaption.getTimeToExpiry(), swaption.isCall());
// Implementation note: option required to pass the strike (in case the swap has non-constant coupon).
final BlackPriceFunction blackFunction = new BlackPriceFunction();
final double[] volatilityAdjoint = sabrData.getSABRParameter().getVolatilityAdjoint(swaption.getTimeToExpiry(), maturity, strikeModified, forwardModified);
final BlackFunctionData dataBlack = new BlackFunctionData(forwardModified, 1.0, volatilityAdjoint[0]);
final Function1D<BlackFunctionData, Double> func = blackFunction.getPriceFunction(option);
final MultipleCurrencyAmount pv = MultipleCurrencyAmount.of(swaption.getCurrency(), pvbpModified * func.evaluate(dataBlack) * (swaption.isLong() ? 1.0 : -1.0));
// Curve sensitivity
final MulticurveSensitivity pvbpModifiedDr = METHOD_SWAP.presentValueBasisPointCurveSensitivity(swaption.getUnderlyingSwap(), dayCountModification, sabrData.getMulticurveProvider());
final MulticurveSensitivity forwardModifiedDr = PRCSDC.visitFixedCouponSwap(swaption.getUnderlyingSwap(), dayCountModification, sabrData.getMulticurveProvider());
final double[] bsAdjoint = blackFunction.getPriceAdjoint(option, dataBlack);
MulticurveSensitivity result = pvbpModifiedDr.multipliedBy(bsAdjoint[0]);
result = result.plus(forwardModifiedDr.multipliedBy(pvbpModified * (bsAdjoint[1] + bsAdjoint[2] * volatilityAdjoint[1])));
if (!swaption.isLong()) {
result = result.multipliedBy(-1);
}