/// <summary>
/// Solve using a user supplied NonLinearParameterTransforms.
/// <para>
/// This returns <seealso cref="LeastSquareResults"/>.
///
/// </para>
/// </summary>
/// <param name="start"> the first guess at the parameter values </param>
/// <param name="transform"> transform from model parameters to fitting parameters, and vice versa </param>
/// <returns> the calibration results </returns>
public virtual LeastSquareResultsWithTransform solve(DoubleArray start, NonLinearParameterTransforms transform)
{
NonLinearTransformFunction transFunc = new NonLinearTransformFunction(volFunc, volAdjointFunc, transform);
LeastSquareResults solRes = SOLVER.solve(marketValues, errors, transFunc.FittingFunction, transFunc.FittingJacobian, transform.transform(start), getConstraintFunction(transform), MaximumStep);
return(new LeastSquareResultsWithTransform(solRes, transform));
}
//JAVA TO C# CONVERTER TODO TASK: Most Java annotations will not have direct .NET equivalent attributes:
//ORIGINAL LINE: @Test public void solverTest()
public virtual void solverTest()
{
double[] w = new double[] { 0.01, 0.5, 0.3, 0.19 };
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final int n = w.length;
int n = w.Length;
//JAVA TO C# CONVERTER WARNING: The original Java variable was marked 'final':
//ORIGINAL LINE: final SumToOne trans = new SumToOne(n);
SumToOne trans = new SumToOne(n);
System.Func <DoubleArray, DoubleArray> func = (DoubleArray theta) =>
{
return(trans.transform(theta));
};
DoubleArray sigma = DoubleArray.filled(n, 1e-4);
DoubleArray start = DoubleArray.filled(n - 1, 0.8);
LeastSquareResults res = SOLVER.solve(DoubleArray.copyOf(w), sigma, func, start);
assertEquals("chi sqr", 0.0, res.ChiSq, 1e-9);
double[] fit = res.FitParameters.toArray();
double[] expected = trans.inverseTransform(w);
for (int i = 0; i < n - 1; i++)
{
//put the fit result back in the range 0 - pi/2
double x = fit[i];
if (x < 0)
{
x = -x;
}
if (x > Math.PI / 2)
{
int p = (int)(x / Math.PI);
x -= p * Math.PI;
if (x > Math.PI / 2)
{
x = -x + Math.PI;
}
}
assertEquals(expected[i], x, 1e-9);
}
}
//-------------------------------------------------------------------------
public override IborCapletFloorletVolatilityCalibrationResult calibrate(IborCapletFloorletVolatilityDefinition definition, ZonedDateTime calibrationDateTime, RawOptionData capFloorData, RatesProvider ratesProvider)
{
ArgChecker.isTrue(ratesProvider.ValuationDate.Equals(calibrationDateTime.toLocalDate()), "valuationDate of ratesProvider should be coherent to calibrationDateTime");
ArgChecker.isTrue(definition is SabrIborCapletFloorletVolatilityCalibrationDefinition, "definition should be SabrIborCapletFloorletVolatilityCalibrationDefinition");
SabrIborCapletFloorletVolatilityCalibrationDefinition sabrDefinition = (SabrIborCapletFloorletVolatilityCalibrationDefinition)definition;
// unpack cap data, create node caps
IborIndex index = sabrDefinition.Index;
LocalDate calibrationDate = calibrationDateTime.toLocalDate();
LocalDate baseDate = index.EffectiveDateOffset.adjust(calibrationDate, ReferenceData);
LocalDate startDate = baseDate.plus(index.Tenor);
System.Func <Surface, IborCapletFloorletVolatilities> volatilitiesFunction = this.volatilitiesFunction(sabrDefinition, calibrationDateTime, capFloorData);
SurfaceMetadata metadata = sabrDefinition.createMetadata(capFloorData);
IList <Period> expiries = capFloorData.Expiries;
DoubleArray strikes = capFloorData.Strikes;
int nExpiries = expiries.Count;
IList <double> timeList = new List <double>();
IList <double> strikeList = new List <double>();
IList <double> volList = new List <double>();
IList <ResolvedIborCapFloorLeg> capList = new List <ResolvedIborCapFloorLeg>();
IList <double> priceList = new List <double>();
IList <double> errorList = new List <double>();
DoubleMatrix errorMatrix = capFloorData.Error.orElse(DoubleMatrix.filled(nExpiries, strikes.size(), 1d));
int[] startIndex = new int[nExpiries + 1];
for (int i = 0; i < nExpiries; ++i)
{
LocalDate endDate = baseDate.plus(expiries[i]);
DoubleArray volatilityForTime = capFloorData.Data.row(i);
DoubleArray errorForTime = errorMatrix.row(i);
reduceRawData(sabrDefinition, ratesProvider, capFloorData.Strikes, volatilityForTime, errorForTime, startDate, endDate, metadata, volatilitiesFunction, timeList, strikeList, volList, capList, priceList, errorList);
startIndex[i + 1] = volList.Count;
ArgChecker.isTrue(startIndex[i + 1] > startIndex[i], "no valid option data for {}", expiries[i]);
}
// create initial caplet vol surface
IList <CurveMetadata> metadataList = sabrDefinition.createSabrParameterMetadata();
DoubleArray initialValues = sabrDefinition.createFullInitialValues();
IList <Curve> curveList = sabrDefinition.createSabrParameterCurve(metadataList, initialValues);
SabrParameters sabrParamsInitial = SabrParameters.of(curveList[0], curveList[1], curveList[2], curveList[3], sabrDefinition.ShiftCurve, sabrDefinition.SabrVolatilityFormula);
SabrParametersIborCapletFloorletVolatilities vols = SabrParametersIborCapletFloorletVolatilities.of(sabrDefinition.Name, index, calibrationDateTime, sabrParamsInitial);
// solve least square
UncoupledParameterTransforms transform = new UncoupledParameterTransforms(initialValues, sabrDefinition.createFullTransform(TRANSFORMS), new BitArray());
System.Func <DoubleArray, DoubleArray> valueFunction = createPriceFunction(sabrDefinition, ratesProvider, vols, capList, priceList);
System.Func <DoubleArray, DoubleMatrix> jacobianFunction = createJacobianFunction(sabrDefinition, ratesProvider, vols, capList, priceList, index.Currency);
NonLinearTransformFunction transFunc = new NonLinearTransformFunction(valueFunction, jacobianFunction, transform);
LeastSquareResults res = solver.solve(DoubleArray.filled(priceList.Count, 1d), DoubleArray.copyOf(errorList), transFunc.FittingFunction, transFunc.FittingJacobian, transform.transform(initialValues));
LeastSquareResultsWithTransform resTransform = new LeastSquareResultsWithTransform(res, transform);
vols = updateParameters(sabrDefinition, vols, resTransform.ModelParameters);
return(IborCapletFloorletVolatilityCalibrationResult.ofLeastSquare(vols, res.ChiSq));
}
//-------------------------------------------------------------------------
public override IborCapletFloorletVolatilityCalibrationResult calibrate(IborCapletFloorletVolatilityDefinition definition, ZonedDateTime calibrationDateTime, RawOptionData capFloorData, RatesProvider ratesProvider)
{
ArgChecker.isTrue(ratesProvider.ValuationDate.Equals(calibrationDateTime.toLocalDate()), "valuationDate of ratesProvider should be coherent to calibrationDateTime");
ArgChecker.isTrue(definition is SabrIborCapletFloorletVolatilityBootstrapDefinition, "definition should be SabrIborCapletFloorletVolatilityBootstrapDefinition");
SabrIborCapletFloorletVolatilityBootstrapDefinition bsDefinition = (SabrIborCapletFloorletVolatilityBootstrapDefinition)definition;
IborIndex index = bsDefinition.Index;
LocalDate calibrationDate = calibrationDateTime.toLocalDate();
LocalDate baseDate = index.EffectiveDateOffset.adjust(calibrationDate, ReferenceData);
LocalDate startDate = baseDate.plus(index.Tenor);
System.Func <Surface, IborCapletFloorletVolatilities> volatilitiesFunction = this.volatilitiesFunction(bsDefinition, calibrationDateTime, capFloorData);
SurfaceMetadata metaData = bsDefinition.createMetadata(capFloorData);
IList <Period> expiries = capFloorData.Expiries;
int nExpiries = expiries.Count;
DoubleArray strikes = capFloorData.Strikes;
DoubleMatrix errorsMatrix = capFloorData.Error.orElse(DoubleMatrix.filled(nExpiries, strikes.size(), 1d));
IList <double> timeList = new List <double>();
IList <double> strikeList = new List <double>();
IList <double> volList = new List <double>();
IList <ResolvedIborCapFloorLeg> capList = new List <ResolvedIborCapFloorLeg>();
IList <double> priceList = new List <double>();
IList <double> errorList = new List <double>();
int[] startIndex = new int[nExpiries + 1];
for (int i = 0; i < nExpiries; ++i)
{
LocalDate endDate = baseDate.plus(expiries[i]);
DoubleArray volatilityData = capFloorData.Data.row(i);
DoubleArray errors = errorsMatrix.row(i);
reduceRawData(bsDefinition, ratesProvider, strikes, volatilityData, errors, startDate, endDate, metaData, volatilitiesFunction, timeList, strikeList, volList, capList, priceList, errorList);
startIndex[i + 1] = volList.Count;
ArgChecker.isTrue(startIndex[i + 1] > startIndex[i], "no valid option data for {}", expiries[i]);
}
IList <CurveMetadata> metadataList = bsDefinition.createSabrParameterMetadata();
DoubleArray timeToExpiries = DoubleArray.of(nExpiries, i => timeList[startIndex[i]]);
BitArray @fixed = new BitArray();
bool betaFix = false;
Curve betaCurve;
Curve rhoCurve;
if (bsDefinition.BetaCurve.Present)
{
betaFix = true;
@fixed.Set(1, true);
betaCurve = bsDefinition.BetaCurve.get();
rhoCurve = InterpolatedNodalCurve.of(metadataList[2], timeToExpiries, DoubleArray.filled(nExpiries), bsDefinition.Interpolator, bsDefinition.ExtrapolatorLeft, bsDefinition.ExtrapolatorRight);
}
else
{
@fixed.Set(2, true);
betaCurve = InterpolatedNodalCurve.of(metadataList[1], timeToExpiries, DoubleArray.filled(nExpiries), bsDefinition.Interpolator, bsDefinition.ExtrapolatorLeft, bsDefinition.ExtrapolatorRight);
rhoCurve = bsDefinition.RhoCurve.get();
}
InterpolatedNodalCurve alphaCurve = InterpolatedNodalCurve.of(metadataList[0], timeToExpiries, DoubleArray.filled(nExpiries), bsDefinition.Interpolator, bsDefinition.ExtrapolatorLeft, bsDefinition.ExtrapolatorRight);
InterpolatedNodalCurve nuCurve = InterpolatedNodalCurve.of(metadataList[3], timeToExpiries, DoubleArray.filled(nExpiries), bsDefinition.Interpolator, bsDefinition.ExtrapolatorLeft, bsDefinition.ExtrapolatorRight);
Curve shiftCurve = bsDefinition.ShiftCurve;
SabrParameters sabrParams = SabrParameters.of(alphaCurve, betaCurve, rhoCurve, nuCurve, shiftCurve, bsDefinition.SabrVolatilityFormula);
SabrParametersIborCapletFloorletVolatilities vols = SabrParametersIborCapletFloorletVolatilities.of(bsDefinition.Name, index, calibrationDateTime, sabrParams);
double totalChiSq = 0d;
ZonedDateTime prevExpiry = calibrationDateTime.minusDays(1L); // included if calibrationDateTime == fixingDateTime
for (int i = 0; i < nExpiries; ++i)
{
DoubleArray start = computeInitialValues(ratesProvider, betaCurve, shiftCurve, timeList, volList, capList, startIndex, i, betaFix, capFloorData.DataType);
UncoupledParameterTransforms transform = new UncoupledParameterTransforms(start, TRANSFORMS, @fixed);
int nCaplets = startIndex[i + 1] - startIndex[i];
int currentStart = startIndex[i];
System.Func <DoubleArray, DoubleArray> valueFunction = createPriceFunction(ratesProvider, vols, prevExpiry, capList, priceList, startIndex, nExpiries, i, nCaplets, betaFix);
System.Func <DoubleArray, DoubleMatrix> jacobianFunction = createJacobianFunction(ratesProvider, vols, prevExpiry, capList, priceList, index.Currency, startIndex, nExpiries, i, nCaplets, betaFix);
NonLinearTransformFunction transFunc = new NonLinearTransformFunction(valueFunction, jacobianFunction, transform);
DoubleArray adjustedPrices = this.adjustedPrices(ratesProvider, vols, prevExpiry, capList, priceList, startIndex, i, nCaplets);
DoubleArray errors = DoubleArray.of(nCaplets, n => errorList[currentStart + n]);
LeastSquareResults res = solver.solve(adjustedPrices, errors, transFunc.FittingFunction, transFunc.FittingJacobian, transform.transform(start));
LeastSquareResultsWithTransform resTransform = new LeastSquareResultsWithTransform(res, transform);
vols = updateParameters(vols, nExpiries, i, betaFix, resTransform.ModelParameters);
totalChiSq += res.ChiSq;
prevExpiry = capList[startIndex[i + 1] - 1].FinalFixingDateTime;
}
return(IborCapletFloorletVolatilityCalibrationResult.ofLeastSquare(vols, totalChiSq));
}