//-------------------------------------------------------------------------
// Compute the approximated rate in the case where the whole period is forward.
// There is no need to compute overnight periods, except for the cut-off period.
private double rateForward(OvernightAveragedRateComputation computation, OvernightIndexRates rates)
{
OvernightIndex index = computation.Index;
HolidayCalendar calendar = computation.FixingCalendar;
LocalDate startFixingDate = computation.StartDate;
LocalDate endFixingDateP1 = computation.EndDate;
LocalDate endFixingDate = calendar.previous(endFixingDateP1);
LocalDate onRateEndDate = computation.calculateMaturityFromFixing(endFixingDate);
LocalDate onRateStartDate = computation.calculateEffectiveFromFixing(startFixingDate);
LocalDate onRateNoCutOffEndDate = onRateEndDate;
int cutoffOffset = computation.RateCutOffDays > 1 ? computation.RateCutOffDays : 1;
double accumulatedInterest = 0.0d;
double accrualFactorTotal = index.DayCount.yearFraction(onRateStartDate, onRateEndDate);
if (cutoffOffset > 1)
{ // Cut-off period
LocalDate currentFixingDate = endFixingDate;
OvernightIndexObservation lastIndexObs = null;
double cutOffAccrualFactorTotal = 0d;
for (int i = 1; i < cutoffOffset; i++)
{
currentFixingDate = calendar.previous(currentFixingDate);
lastIndexObs = computation.observeOn(currentFixingDate);
onRateNoCutOffEndDate = lastIndexObs.MaturityDate;
cutOffAccrualFactorTotal += lastIndexObs.YearFraction;
}
double forwardRateCutOff = rates.rate(lastIndexObs);
accumulatedInterest += cutOffAccrualFactorTotal * forwardRateCutOff;
}
// Approximated part
accumulatedInterest += approximatedInterest(computation.observeOn(onRateStartDate), onRateNoCutOffEndDate, rates);
// final rate
return(accumulatedInterest / accrualFactorTotal);
}
private PointSensitivityBuilder rateForwardSensitivity(OvernightAveragedRateComputation computation, OvernightIndexRates rates)
{
OvernightIndex index = computation.Index;
HolidayCalendar calendar = computation.FixingCalendar;
LocalDate startFixingDate = computation.StartDate;
LocalDate endFixingDateP1 = computation.EndDate;
LocalDate endFixingDate = calendar.previous(endFixingDateP1);
LocalDate onRateEndDate = computation.calculateMaturityFromFixing(endFixingDate);
LocalDate onRateStartDate = computation.calculateEffectiveFromFixing(startFixingDate);
LocalDate lastNonCutOffMatDate = onRateEndDate;
int cutoffOffset = computation.RateCutOffDays > 1 ? computation.RateCutOffDays : 1;
PointSensitivityBuilder combinedPointSensitivityBuilder = PointSensitivityBuilder.none();
double accrualFactorTotal = index.DayCount.yearFraction(onRateStartDate, onRateEndDate);
if (cutoffOffset > 1)
{ // Cut-off period
IList <double> noCutOffAccrualFactorList = new List <double>();
LocalDate currentFixingDate = endFixingDateP1;
LocalDate cutOffEffectiveDate;
for (int i = 0; i < cutoffOffset; i++)
{
currentFixingDate = calendar.previous(currentFixingDate);
cutOffEffectiveDate = computation.calculateEffectiveFromFixing(currentFixingDate);
lastNonCutOffMatDate = computation.calculateMaturityFromEffective(cutOffEffectiveDate);
double accrualFactor = index.DayCount.yearFraction(cutOffEffectiveDate, lastNonCutOffMatDate);
noCutOffAccrualFactorList.Add(accrualFactor);
}
OvernightIndexObservation lastIndexObs = computation.observeOn(currentFixingDate);
PointSensitivityBuilder forwardRateCutOffSensitivity = rates.ratePointSensitivity(lastIndexObs);
double totalAccrualFactor = 0.0;
for (int i = 0; i < cutoffOffset - 1; i++)
{
totalAccrualFactor += noCutOffAccrualFactorList[i];
}
forwardRateCutOffSensitivity = forwardRateCutOffSensitivity.multipliedBy(totalAccrualFactor);
combinedPointSensitivityBuilder = combinedPointSensitivityBuilder.combinedWith(forwardRateCutOffSensitivity);
}
// Approximated part
OvernightIndexObservation indexObs = computation.observeOn(onRateStartDate);
PointSensitivityBuilder approximatedInterestAndSensitivity = approximatedInterestSensitivity(indexObs, lastNonCutOffMatDate, rates);
combinedPointSensitivityBuilder = combinedPointSensitivityBuilder.combinedWith(approximatedInterestAndSensitivity);
combinedPointSensitivityBuilder = combinedPointSensitivityBuilder.multipliedBy(1.0 / accrualFactorTotal);
// final rate
return(combinedPointSensitivityBuilder);
}