com.opengamma.strata.pricer.swaption.NormalSwaptionCashParYieldProductPricer Maven / Gradle / Ivy
/*
* Copyright (C) 2015 - present by OpenGamma Inc. and the OpenGamma group of companies
*
* Please see distribution for license.
*/
package com.opengamma.strata.pricer.swaption;
import java.time.LocalDate;
import java.time.ZonedDateTime;
import com.opengamma.strata.basics.date.DayCount;
import com.opengamma.strata.collect.ArgChecker;
import com.opengamma.strata.pricer.impl.option.NormalFormulaRepository;
import com.opengamma.strata.pricer.rate.RatesProvider;
import com.opengamma.strata.pricer.swap.DiscountingSwapProductPricer;
import com.opengamma.strata.product.common.PutCall;
import com.opengamma.strata.product.swap.ResolvedSwap;
import com.opengamma.strata.product.swap.ResolvedSwapLeg;
import com.opengamma.strata.product.swap.Swap;
import com.opengamma.strata.product.swaption.ResolvedSwaption;
/**
* Pricer for swaption with par yield curve method of cash settlement in a normal model on the swap rate.
*
* The swap underlying the swaption must have a fixed leg on which the forward rate is computed.
* The underlying swap must be single currency.
*
* The volatility parameters are not adjusted for the underlying swap convention.
*
* The value of the swaption after expiry is 0.
* For a swaption which already expired, negative number is returned by
* {@link SwaptionVolatilities#relativeTime(ZonedDateTime)}.
*/
public class NormalSwaptionCashParYieldProductPricer
extends VolatilitySwaptionCashParYieldProductPricer {
/**
* Default implementation.
*/
public static final NormalSwaptionCashParYieldProductPricer DEFAULT =
new NormalSwaptionCashParYieldProductPricer(DiscountingSwapProductPricer.DEFAULT);
/**
* Creates an instance.
*
* @param swapPricer the pricer for {@link Swap}
*/
public NormalSwaptionCashParYieldProductPricer(DiscountingSwapProductPricer swapPricer) {
super(swapPricer);
}
//-------------------------------------------------------------------------
/**
* Computes the implied normal volatility from the present value of a swaption.
*
* The guess volatility for the start of the root-finding process is 1%.
*
* @param swaption the product
* @param ratesProvider the rates provider
* @param dayCount the day-count used to estimate the time between valuation date and swaption expiry
* @param presentValue the present value of the swaption product
* @return the implied volatility associated with the present value
*/
public double impliedVolatilityFromPresentValue(
ResolvedSwaption swaption,
RatesProvider ratesProvider,
DayCount dayCount,
double presentValue) {
double sign = swaption.getLongShort().sign();
ArgChecker.isTrue(presentValue * sign > 0, "Present value sign must be in line with the option Long/Short flag ");
validateSwaption(swaption);
LocalDate valuationDate = ratesProvider.getValuationDate();
LocalDate expiryDate = swaption.getExpiryDate();
ArgChecker.isTrue(expiryDate.isAfter(valuationDate),
"Expiry must be after valuation date to compute an implied volatility");
double expiry = dayCount.yearFraction(valuationDate, expiryDate);
ResolvedSwap underlying = swaption.getUnderlying();
ResolvedSwapLeg fixedLeg = fixedLeg(underlying);
double forward = forwardRate(swaption, ratesProvider);
double numeraire = calculateNumeraire(swaption, fixedLeg, forward, ratesProvider);
double strike = calculateStrike(fixedLeg);
PutCall putCall = PutCall.ofPut(fixedLeg.getPayReceive().isReceive());
return NormalFormulaRepository.impliedVolatility(
Math.abs(presentValue), forward, strike, expiry, 0.01, numeraire, putCall);
}
}