//-------------------------------------------------------------------------
/// <summary>
/// Calculates the present value rates sensitivity of the Ibor caplet/floorlet.
/// <para>
/// The present value rates sensitivity of the caplet/floorlet is the sensitivity
/// of the present value to the underlying curves.
///
/// </para>
/// </summary>
/// <param name="period"> the Ibor caplet/floorlet period </param>
/// <param name="ratesProvider"> the rates provider </param>
/// <param name="volatilities"> the volatilities </param>
/// <returns> the present value curve sensitivity </returns>
public virtual PointSensitivityBuilder presentValueSensitivityRates(IborCapletFloorletPeriod period, RatesProvider ratesProvider, IborCapletFloorletVolatilities volatilities)
{
validate(volatilities);
Currency currency = period.Currency;
if (ratesProvider.ValuationDate.isAfter(period.PaymentDate))
{
return(PointSensitivityBuilder.none());
}
double expiry = volatilities.relativeTime(period.FixingDateTime);
PutCall putCall = period.PutCall;
double strike = period.Strike;
double indexRate = ratesProvider.iborIndexRates(period.Index).rate(period.IborRate.Observation);
PointSensitivityBuilder dfSensi = ratesProvider.discountFactors(currency).zeroRatePointSensitivity(period.PaymentDate);
if (expiry < 0d)
{ // Option has expired already
double sign = putCall.Call ? 1d : -1d;
double payoff = Math.Max(sign * (indexRate - strike), 0d);
return(dfSensi.multipliedBy(payoff * period.YearFraction * period.Notional));
}
PointSensitivityBuilder indexRateSensiSensi = ratesProvider.iborIndexRates(period.Index).ratePointSensitivity(period.IborRate.Observation);
double volatility = volatilities.volatility(expiry, strike, indexRate);
double df = ratesProvider.discountFactor(currency, period.PaymentDate);
double factor = period.Notional * period.YearFraction;
double fwdPv = factor * volatilities.price(expiry, putCall, strike, indexRate, volatility);
double fwdDelta = factor * volatilities.priceDelta(expiry, putCall, strike, indexRate, volatility);
return(dfSensi.multipliedBy(fwdPv).combinedWith(indexRateSensiSensi.multipliedBy(fwdDelta * df)));
}
/// <summary>
/// Test for the case where publication lag=0, effective offset=0 (GBP conventions) and no cutoff period.
/// The arithmetic average coupons are used mainly in USD. This test is more for completeness than a real case.
/// </summary>
public virtual void rateGbpNoCutOffSensitivity()
{
OvernightIndexRates mockRates = mock(typeof(OvernightIndexRates));
when(mockRates.Index).thenReturn(GBP_SONIA);
SimpleRatesProvider simpleProv = new SimpleRatesProvider(mockRates);
for (int i = 0; i < GBP_OBS.Length; i++)
{
when(mockRates.rate(GBP_OBS[i])).thenReturn(FIXING_RATES[i]);
OvernightRateSensitivity sensitivity = OvernightRateSensitivity.of(GBP_OBS[i], GBP_SONIA.Currency, 1d);
when(mockRates.ratePointSensitivity(GBP_OBS[i])).thenReturn(sensitivity);
}
OvernightAveragedRateComputation ro = OvernightAveragedRateComputation.of(GBP_SONIA, START_DATE, END_DATE, 0, REF_DATA);
ForwardOvernightAveragedRateComputationFn obsFn = ForwardOvernightAveragedRateComputationFn.DEFAULT;
PointSensitivityBuilder sensitivityBuilderComputed = obsFn.rateSensitivity(ro, DUMMY_ACCRUAL_START_DATE, DUMMY_ACCRUAL_END_DATE, simpleProv);
PointSensitivities sensitivityComputed = sensitivityBuilderComputed.build().normalized();
double?[] sensitivityExpected = computedSensitivityFD(ro, GBP_SONIA, GBP_OBS);
assertEquals(sensitivityComputed.Sensitivities.size(), sensitivityExpected.Length);
for (int i = 0; i < sensitivityExpected.Length; ++i)
{
assertEquals(sensitivityComputed.Sensitivities.get(i).Sensitivity, sensitivityExpected[i], EPS_FD);
}
}
