//-------------------------------------------------------------------------
public virtual void coverage()
{
coverImmutableBean(VOLS);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities vols = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(USD_LIBOR_3M, VAL_DATE_TIME.plusMonths(1), InterpolatedNodalSurface.of(METADATA, TIME, STRIKE, VOL, GridSurfaceInterpolator.of(TIME_SQUARE, LINEAR)), ConstantCurve.of("shift", 0.05));
coverBeanEquals(VOLS, vols);
}
public virtual void recovery_test_shiftedBlack()
{
double lambdaT = 0.07;
double lambdaK = 0.07;
double error = 1.0e-5;
ConstantCurve shiftCurve = ConstantCurve.of("Black shift", 0.02);
DirectIborCapletFloorletVolatilityDefinition definition = DirectIborCapletFloorletVolatilityDefinition.of(NAME, USD_LIBOR_3M, ACT_ACT_ISDA, lambdaT, lambdaK, INTERPOLATOR, shiftCurve);
ImmutableList <Period> maturities = createBlackMaturities();
DoubleArray strikes = createBlackStrikes();
DoubleMatrix errorMatrix = DoubleMatrix.filled(maturities.size(), strikes.size(), error);
RawOptionData data = RawOptionData.of(maturities, strikes, STRIKE, createFullBlackDataMatrix(), errorMatrix, BLACK_VOLATILITY);
IborCapletFloorletVolatilityCalibrationResult res = CALIBRATOR.calibrate(definition, CALIBRATION_TIME, data, RATES_PROVIDER);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities resVols = (ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities)res.Volatilities;
for (int i = 0; i < NUM_BLACK_STRIKES; ++i)
{
Pair <IList <ResolvedIborCapFloorLeg>, IList <double> > capsAndVols = getCapsBlackVols(i);
IList <ResolvedIborCapFloorLeg> caps = capsAndVols.First;
IList <double> vols = capsAndVols.Second;
int nCaps = caps.Count;
for (int j = 0; j < nCaps; ++j)
{
ConstantSurface volSurface = ConstantSurface.of(Surfaces.blackVolatilityByExpiryStrike("test", ACT_ACT_ISDA), vols[j]);
BlackIborCapletFloorletExpiryStrikeVolatilities constVol = BlackIborCapletFloorletExpiryStrikeVolatilities.of(USD_LIBOR_3M, CALIBRATION_TIME, volSurface);
double priceOrg = LEG_PRICER_BLACK.presentValue(caps[j], RATES_PROVIDER, constVol).Amount;
double priceCalib = LEG_PRICER_BLACK.presentValue(caps[j], RATES_PROVIDER, resVols).Amount;
assertEquals(priceOrg, priceCalib, Math.Max(priceOrg, 1d) * TOL);
}
}
assertTrue(res.ChiSquare > 0d);
assertEquals(resVols.Index, USD_LIBOR_3M);
assertEquals(resVols.Name, definition.Name);
assertEquals(resVols.ValuationDateTime, CALIBRATION_TIME);
assertEquals(resVols.ShiftCurve, definition.ShiftCurve.get());
}
public virtual void test_volatility_sensitivity()
{
double eps = 1.0e-6;
int nData = TIME.size();
for (int i = 0; i < NB_TEST; i++)
{
for (int k = 0; k < NB_TEST; k++)
{
double expiryTime = VOLS.relativeTime(TEST_OPTION_EXPIRY[i]);
IborCapletFloorletSensitivity point = IborCapletFloorletSensitivity.of(VOLS.Name, expiryTime, TEST_STRIKE[k], TEST_FORWARD, GBP, TEST_SENSITIVITY[i]);
double[] sensFd = new double[nData];
for (int j = 0; j < nData; j++)
{
DoubleArray volDataUp = VOL.subArray(0, nData).with(j, VOL.get(j) + eps);
DoubleArray volDataDw = VOL.subArray(0, nData).with(j, VOL.get(j) - eps);
InterpolatedNodalSurface paramUp = InterpolatedNodalSurface.of(METADATA, TIME, STRIKE, volDataUp, INTERPOLATOR_2D);
InterpolatedNodalSurface paramDw = InterpolatedNodalSurface.of(METADATA, TIME, STRIKE, volDataDw, INTERPOLATOR_2D);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities provUp = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(GBP_LIBOR_3M, VAL_DATE_TIME, paramUp, CURVE);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities provDw = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(GBP_LIBOR_3M, VAL_DATE_TIME, paramDw, CURVE);
double volUp = provUp.volatility(TEST_OPTION_EXPIRY[i], TEST_STRIKE[k], TEST_FORWARD);
double volDw = provDw.volatility(TEST_OPTION_EXPIRY[i], TEST_STRIKE[k], TEST_FORWARD);
double fd = 0.5 * (volUp - volDw) / eps;
sensFd[j] = fd * TEST_SENSITIVITY[i];
}
CurrencyParameterSensitivity sensActual = VOLS.parameterSensitivity(point).Sensitivities.get(0);
double[] computed = sensActual.Sensitivity.toArray();
assertTrue(DoubleArrayMath.fuzzyEquals(computed, sensFd, eps));
}
}
}
public virtual void recovery_test_normal2_shift()
{
SurfaceIborCapletFloorletVolatilityBootstrapDefinition definition = SurfaceIborCapletFloorletVolatilityBootstrapDefinition.of(IborCapletFloorletVolatilitiesName.of("test"), USD_LIBOR_3M, ACT_ACT_ISDA, LINEAR, DOUBLE_QUADRATIC, ConstantCurve.of("Black shift", 0.02));
DoubleArray strikes = createNormalEquivStrikes();
RawOptionData data = RawOptionData.of(createNormalEquivMaturities(), strikes, ValueType.STRIKE, createFullNormalEquivDataMatrix(), ValueType.NORMAL_VOLATILITY);
IborCapletFloorletVolatilityCalibrationResult res = CALIBRATOR.calibrate(definition, CALIBRATION_TIME, data, RATES_PROVIDER);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities resVol = (ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities)res.Volatilities;
for (int i = 0; i < strikes.size(); ++i)
{
Pair <IList <ResolvedIborCapFloorLeg>, IList <double> > capsAndVols = getCapsNormalEquivVols(i);
IList <ResolvedIborCapFloorLeg> caps = capsAndVols.First;
IList <double> vols = capsAndVols.Second;
int nCaps = caps.Count;
for (int j = 0; j < nCaps; ++j)
{
ConstantSurface volSurface = ConstantSurface.of(Surfaces.normalVolatilityByExpiryStrike("test", ACT_ACT_ISDA), vols[j]);
NormalIborCapletFloorletExpiryStrikeVolatilities constVol = NormalIborCapletFloorletExpiryStrikeVolatilities.of(USD_LIBOR_3M, CALIBRATION_TIME, volSurface);
double priceOrg = LEG_PRICER_NORMAL.presentValue(caps[j], RATES_PROVIDER, constVol).Amount;
double priceCalib = LEG_PRICER_BLACK.presentValue(caps[j], RATES_PROVIDER, resVol).Amount;
assertEquals(priceOrg, priceCalib, Math.Max(priceOrg, 1d) * TOL);
}
}
assertEquals(res.ChiSquare, 0d);
}
private System.Func <Surface, IborCapletFloorletVolatilities> createShiftedBlackVolatilitiesFunction(IborIndex index, ZonedDateTime calibrationDateTime, Curve shiftCurve)
{
System.Func <Surface, IborCapletFloorletVolatilities> func = (Surface s) =>
{
return(ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(index, calibrationDateTime, s, shiftCurve));
};
return(func);
}
//-----------------------------------------------------------------------
public override bool Equals(object obj)
{
if (obj == this)
{
return(true);
}
if (obj != null && obj.GetType() == this.GetType())
{
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities other = (ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities)obj;
return(JodaBeanUtils.equal(index, other.index) && JodaBeanUtils.equal(valuationDateTime, other.valuationDateTime) && JodaBeanUtils.equal(surface, other.surface) && JodaBeanUtils.equal(shiftCurve, other.shiftCurve));
}
return(false);
}
private void testSurfaceSensitivity(CurrencyParameterSensitivity computed, ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities vols, System.Func <IborCapletFloorletVolatilities, CurrencyAmount> valueFn)
{
double pvBase = valueFn(vols).Amount;
InterpolatedNodalSurface surfaceBase = (InterpolatedNodalSurface)vols.Surface;
int nParams = surfaceBase.ParameterCount;
for (int i = 0; i < nParams; i++)
{
DoubleArray zBumped = surfaceBase.ZValues.with(i, surfaceBase.ZValues.get(i) + EPS_FD);
InterpolatedNodalSurface surfaceBumped = surfaceBase.withZValues(zBumped);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities volsBumped = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(vols.Index, vols.ValuationDateTime, surfaceBumped, vols.ShiftCurve);
double fd = (valueFn(volsBumped).Amount - pvBase) / EPS_FD;
assertEquals(computed.Sensitivity.get(i), fd, NOTIONAL * EPS_FD);
}
}
public virtual void test_getter()
{
assertEquals(VOLS.ValuationDate, VAL_DATE);
assertEquals(VOLS.Index, GBP_LIBOR_3M);
assertEquals(VOLS.Surface, SURFACE);
assertEquals(VOLS.ParameterCount, TIME.size());
assertEquals(VOLS.findData(CURVE.Name).get(), CURVE);
assertEquals(VOLS.findData(SURFACE.Name).get(), SURFACE);
assertFalse(VOLS.findData(CurveName.of("foo")).Present);
int nParams = VOLS.ParameterCount;
double newValue = 152d;
for (int i = 0; i < nParams; ++i)
{
assertEquals(VOLS.getParameter(i), SURFACE.getParameter(i));
assertEquals(VOLS.getParameterMetadata(i), SURFACE.getParameterMetadata(i));
assertEquals(VOLS.withParameter(i, newValue), ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(GBP_LIBOR_3M, VAL_DATE_TIME, SURFACE.withParameter(i, newValue), CURVE));
assertEquals(VOLS.withPerturbation((n, v, m) => 2d * v), ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(GBP_LIBOR_3M, VAL_DATE_TIME, SURFACE.withPerturbation((n, v, m) => 2d * v), CURVE));
}
}
//-------------------------------------------------------------------------
public virtual void test_presentValue_formula()
{
CurrencyAmount computedCaplet = PRICER.presentValue(CAPLET_LONG, RATES, VOLS);
CurrencyAmount computedFloorlet = PRICER.presentValue(FLOORLET_SHORT, RATES, VOLS);
double forward = RATES.iborIndexRates(EUR_EURIBOR_3M).rate(RATE_COMP.Observation);
double expiry = VOLS.relativeTime(CAPLET_LONG.FixingDateTime);
double volatility = VOLS.volatility(expiry, STRIKE, forward);
double df = RATES.discountFactor(EUR, CAPLET_LONG.PaymentDate);
double expectedCaplet = NOTIONAL * df * CAPLET_LONG.YearFraction * BlackFormulaRepository.price(forward + SHIFT, STRIKE + SHIFT, expiry, volatility, CALL.Call);
double expectedFloorlet = -NOTIONAL *df *FLOORLET_SHORT.YearFraction *BlackFormulaRepository.price(forward + SHIFT, STRIKE + SHIFT, expiry, volatility, PUT.Call);
assertEquals(computedCaplet.Currency, EUR);
assertEquals(computedCaplet.Amount, expectedCaplet, NOTIONAL * TOL);
assertEquals(computedFloorlet.Currency, EUR);
assertEquals(computedFloorlet.Amount, expectedFloorlet, NOTIONAL * TOL);
// consistency with shifted Black
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities vols = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(EUR_EURIBOR_3M, VALUATION, ConstantSurface.of("constVol", volatility).withMetadata(Surfaces.blackVolatilityByExpiryStrike("costVol", DayCounts.ACT_ACT_ISDA)), IborCapletFloorletSabrRateVolatilityDataSet.CURVE_CONST_SHIFT);
CurrencyAmount computedCapletBlack = PRICER_BASE.presentValue(CAPLET_LONG, RATES, vols);
CurrencyAmount computedFloorletBlack = PRICER_BASE.presentValue(FLOORLET_SHORT, RATES, vols);
assertEquals(computedCaplet.Amount, computedCapletBlack.Amount, NOTIONAL * TOL);
assertEquals(computedFloorlet.Amount, computedFloorletBlack.Amount, NOTIONAL * TOL);
}
public virtual void recovery_test_blackSurface_shift()
{
SurfaceIborCapletFloorletVolatilityBootstrapDefinition definition = SurfaceIborCapletFloorletVolatilityBootstrapDefinition.of(IborCapletFloorletVolatilitiesName.of("test"), USD_LIBOR_3M, ACT_ACT_ISDA, LINEAR, LINEAR, ConstantCurve.of("Black shift", 0.02));
DoubleArray strikes = createBlackStrikes();
RawOptionData data = RawOptionData.of(createBlackMaturities(), strikes, ValueType.STRIKE, createFullBlackDataMatrix(), ValueType.BLACK_VOLATILITY);
IborCapletFloorletVolatilityCalibrationResult res = CALIBRATOR.calibrate(definition, CALIBRATION_TIME, data, RATES_PROVIDER);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities resVol = (ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities)res.Volatilities;
for (int i = 0; i < strikes.size(); ++i)
{
Pair <IList <ResolvedIborCapFloorLeg>, IList <double> > capsAndVols = getCapsBlackVols(i);
IList <ResolvedIborCapFloorLeg> caps = capsAndVols.First;
IList <double> vols = capsAndVols.Second;
int nCaps = caps.Count;
for (int j = 0; j < nCaps; ++j)
{
ConstantSurface volSurface = ConstantSurface.of(Surfaces.blackVolatilityByExpiryStrike("test", ACT_ACT_ISDA), vols[j]);
BlackIborCapletFloorletExpiryStrikeVolatilities constVol = BlackIborCapletFloorletExpiryStrikeVolatilities.of(USD_LIBOR_3M, CALIBRATION_TIME, volSurface);
double priceOrg = LEG_PRICER_BLACK.presentValue(caps[j], RATES_PROVIDER, constVol).Amount;
double priceCalib = LEG_PRICER_BLACK.presentValue(caps[j], RATES_PROVIDER, resVol).Amount;
assertEquals(priceOrg, priceCalib, Math.Max(priceOrg, 1d) * TOL);
}
}
assertEquals(res.ChiSquare, 0d);
assertEquals(resVol.Index, USD_LIBOR_3M);
assertEquals(resVol.Name, definition.Name);
assertEquals(resVol.ValuationDateTime, CALIBRATION_TIME);
assertEquals(resVol.ShiftCurve, definition.ShiftCurve.get());
InterpolatedNodalSurface surface = (InterpolatedNodalSurface)resVol.Surface;
for (int i = 0; i < surface.ParameterCount; ++i)
{
GenericVolatilitySurfacePeriodParameterMetadata metadata = (GenericVolatilitySurfacePeriodParameterMetadata)surface.getParameterMetadata(i);
assertEquals(metadata.Strike.Value + 0.02, surface.YValues.get(i));
}
}
//-------------------------------------------------------------------------
public virtual void test_presentValueSensitivity()
{
PointSensitivityBuilder pointCaplet = PRICER.presentValueSensitivityRatesStickyModel(CAPLET_LONG, RATES, VOLS);
CurrencyParameterSensitivities computedCaplet = RATES.parameterSensitivity(pointCaplet.build());
PointSensitivityBuilder pointFloorlet = PRICER.presentValueSensitivityRatesStickyModel(FLOORLET_SHORT, RATES, VOLS);
CurrencyParameterSensitivities computedFloorlet = RATES.parameterSensitivity(pointFloorlet.build());
CurrencyParameterSensitivities expectedCaplet = FD_CAL.sensitivity(RATES, p => PRICER_BASE.presentValue(CAPLET_LONG, p, VOLS));
CurrencyParameterSensitivities expectedFloorlet = FD_CAL.sensitivity(RATES, p => PRICER_BASE.presentValue(FLOORLET_SHORT, p, VOLS));
assertTrue(computedCaplet.equalWithTolerance(expectedCaplet, EPS_FD * NOTIONAL * 50d));
assertTrue(computedFloorlet.equalWithTolerance(expectedFloorlet, EPS_FD * NOTIONAL * 50d));
// consistency with shifted Black
PointSensitivityBuilder pointCapletBase = PRICER.presentValueSensitivityRates(CAPLET_LONG, RATES, VOLS);
PointSensitivityBuilder pointFloorletBase = PRICER.presentValueSensitivityRates(FLOORLET_SHORT, RATES, VOLS);
double forward = RATES.iborIndexRates(EUR_EURIBOR_3M).rate(RATE_COMP.Observation);
double expiry = VOLS.relativeTime(CAPLET_LONG.FixingDateTime);
double volatility = VOLS.volatility(expiry, STRIKE, forward);
ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities vols = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(EUR_EURIBOR_3M, VALUATION, ConstantSurface.of("constVol", volatility).withMetadata(Surfaces.blackVolatilityByExpiryStrike("costVol", DayCounts.ACT_ACT_ISDA)), IborCapletFloorletSabrRateVolatilityDataSet.CURVE_CONST_SHIFT);
PointSensitivityBuilder pointCapletExp = PRICER_BASE.presentValueSensitivityRates(CAPLET_LONG, RATES, vols);
PointSensitivityBuilder pointFloorletExp = PRICER_BASE.presentValueSensitivityRates(FLOORLET_SHORT, RATES, vols);
assertEquals(pointCapletBase, pointCapletExp);
assertEquals(pointFloorletBase, pointFloorletExp);
}
/// <summary>
/// Creates shifted Black volatilities provider with specified date and index.
/// </summary>
/// <param name="valuationDate"> the valuation date </param>
/// <param name="index"> the index </param>
/// <returns> the volatilities provider </returns>
public static ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities createShiftedBlackVolatilities(ZonedDateTime valuationDate, IborIndex index)
{
return(ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(index, valuationDate, SHIFTED_BLACK_SURFACE_EXP_STR, SHIFT_CURVE));
}
//-------------------------------------------------------------------------
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 SurfaceIborCapletFloorletVolatilityBootstrapDefinition, "definition should be SurfaceIborCapletFloorletVolatilityBootstrapDefinition");
SurfaceIborCapletFloorletVolatilityBootstrapDefinition bsDefinition = (SurfaceIborCapletFloorletVolatilityBootstrapDefinition)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]);
}
int nTotal = startIndex[nExpiries];
IborCapletFloorletVolatilities vols;
int start;
ZonedDateTime prevExpiry;
DoubleArray initialVol = DoubleArray.copyOf(volList);
if (bsDefinition.ShiftCurve.Present)
{
Curve shiftCurve = bsDefinition.ShiftCurve.get();
DoubleArray strikeShifted = DoubleArray.of(nTotal, n => strikeList[n] + shiftCurve.yValue(timeList[n]));
if (capFloorData.DataType.Equals(NORMAL_VOLATILITY))
{ // correct initial surface
metadata = Surfaces.blackVolatilityByExpiryStrike(bsDefinition.Name.Name, bsDefinition.DayCount).withParameterMetadata(metadata.ParameterMetadata.get());
initialVol = DoubleArray.of(nTotal, n => volList[n] / (ratesProvider.iborIndexRates(index).rate(capList[n].FinalPeriod.IborRate.Observation) + shiftCurve.yValue(timeList[n])));
}
InterpolatedNodalSurface surface = InterpolatedNodalSurface.of(metadata, DoubleArray.copyOf(timeList), strikeShifted, initialVol, bsDefinition.Interpolator);
vols = ShiftedBlackIborCapletFloorletExpiryStrikeVolatilities.of(index, calibrationDateTime, surface, bsDefinition.ShiftCurve.get());
start = 0;
prevExpiry = calibrationDateTime.minusDays(1L); // included if calibrationDateTime == fixingDateTime
}
else
{
InterpolatedNodalSurface surface = InterpolatedNodalSurface.of(metadata, DoubleArray.copyOf(timeList), DoubleArray.copyOf(strikeList), initialVol, bsDefinition.Interpolator);
vols = volatilitiesFunction(surface);
start = 1;
prevExpiry = capList[startIndex[1] - 1].FinalFixingDateTime;
}
for (int i = start; i < nExpiries; ++i)
{
for (int j = startIndex[i]; j < startIndex[i + 1]; ++j)
{
System.Func <double, double[]> func = getValueVegaFunction(capList[j], ratesProvider, vols, prevExpiry, j);
GenericImpliedVolatiltySolver solver = new GenericImpliedVolatiltySolver(func);
double priceFixed = i == 0 ? 0d : this.priceFixed(capList[j], ratesProvider, vols, prevExpiry);
double capletVol = solver.impliedVolatility(priceList[j] - priceFixed, initialVol.get(j));
vols = vols.withParameter(j, capletVol);
}
prevExpiry = capList[startIndex[i + 1] - 1].FinalFixingDateTime;
}
return(IborCapletFloorletVolatilityCalibrationResult.ofRootFind(vols));
}