Real LinearTsrPricer::strikeFromVegaRatio(Real ratio,
Option::Type optionType,
Real referenceStrike) const {
Real a, b, min, max, k;
if (optionType == Option::Call) {
a = swapRateValue_;
min = referenceStrike;
b = max = k =
std::min(smileSection_->maxStrike(), adjustedUpperBound_);
} else {
a = min = k =
std::max(smileSection_->minStrike(), adjustedLowerBound_);
b = swapRateValue_;
max = referenceStrike;
}
VegaRatioHelper h(&*smileSection_,
smileSection_->vega(swapRateValue_) * ratio);
Brent solver;
try {
k = solver.solve(h, 1.0E-5, (a + b) / 2.0, a, b);
}
catch (...) {
// use default value set above
}
return std::min(std::max(k, min), max);
}
Spread CallableBond::OAS(Real cleanPrice,
const Handle<YieldTermStructure>& engineTS,
const DayCounter& dayCounter,
Compounding compounding,
Frequency frequency,
Date settlement,
Real accuracy,
Size maxIterations,
Spread guess)
{
if (settlement == Date())
settlement = settlementDate();
Real dirtyPrice = cleanPrice + accruedAmount(settlement);
boost::function<Real(Real)> f = NPVSpreadHelper(*this);
OASHelper obj(f, dirtyPrice);
Brent solver;
solver.setMaxEvaluations(maxIterations);
Real step = 0.001;
Spread oas=solver.solve(obj, accuracy, guess, step);
return continuousToConv(oas,
*this,
engineTS,
dayCounter,
compounding,
frequency);
}
Real LinearTsrPricer::strikeFromPrice(Real price, Option::Type optionType,
Real referenceStrike) const {
Real a, b, min, max, k;
if (optionType == Option::Call) {
a = swapRateValue_;
min = referenceStrike;
b = max = k =
std::min(smileSection_->maxStrike(), settings_.upperRateBound_);
} else {
a = min = k =
std::max(smileSection_->minStrike(), settings_.lowerRateBound_);
b = swapRateValue_;
max = referenceStrike;
}
PriceHelper h(&*smileSection_, optionType, price);
Brent solver;
try {
k = solver.solve(h, 1.0E-5, swapRateValue_, a, b);
}
catch (...) {
// use default value set above
}
return std::min(std::max(k, min), max);
}
Volatility CalibrationHelper::impliedVolatility(Real targetValue,
Real accuracy,
Size maxEvaluations,
Volatility minVol,
Volatility maxVol) const {
ImpliedVolatilityHelper f(*this,targetValue);
Brent solver;
solver.setMaxEvaluations(maxEvaluations);
return solver.solve(f,accuracy,volatility_->value(),minVol,maxVol);
}
double Gamma2Distribution::cumulativeInv(const double p, const bool fast, const long bins) {
if(fast) {
if(!fastCalculated_ || bins!=fastBins_) {
fastBins_=bins;
preCalculateCumulativeInv();
}
return fastCumulativeInv(p);
}
G2InvHelper hlp(this,p);
Brent b;
return b.solve(hlp,INVG2ACC,1.0,0.1);
}
std::vector<Volatility> OptionletStripper2::spreadsVolImplied() const {
Brent solver;
std::vector<Volatility> result(nOptionExpiries_);
Volatility guess = 0.0001, minSpread = -0.1, maxSpread = 0.1;
for (Size j=0; j<nOptionExpiries_; ++j) {
ObjectiveFunction f(stripper1_, caps_[j], atmCapFloorPrices_[j]);
solver.setMaxEvaluations(maxEvaluations_);
Volatility root = solver.solve(f, accuracy_, guess,
minSpread, maxSpread);
result[j] = root;
}
return result;
}
Volatility CallableBond::impliedVolatility(
Real targetValue,
const Handle<YieldTermStructure>& discountCurve,
Real accuracy,
Size maxEvaluations,
Volatility minVol,
Volatility maxVol) const {
calculate();
QL_REQUIRE(!isExpired(), "instrument expired");
Volatility guess = 0.5*(minVol + maxVol);
blackDiscountCurve_.linkTo(*discountCurve, false);
ImpliedVolHelper f(*this,targetValue);
Brent solver;
solver.setMaxEvaluations(maxEvaluations);
return solver.solve(f, accuracy, guess, minVol, maxVol);
}
Volatility HestonBlackVolSurface::blackVolImpl(Time t, Real strike) const {
const boost::shared_ptr<HestonProcess> process = hestonModel_->process();
const DiscountFactor df = process->riskFreeRate()->discount(t, true);
const DiscountFactor div = process->dividendYield()->discount(t, true);
const Real spotPrice = process->s0()->value();
const Real fwd = spotPrice
* process->dividendYield()->discount(t, true)
/ process->riskFreeRate()->discount(t, true);
const PlainVanillaPayoff payoff(
fwd > strike ? Option::Put : Option::Call, strike);
const Real kappa = hestonModel_->kappa();
const Real theta = hestonModel_->theta();
const Real rho = hestonModel_->rho();
const Real sigma = hestonModel_->sigma();
const Real v0 = hestonModel_->v0();
const AnalyticHestonEngine::ComplexLogFormula cpxLogFormula
= AnalyticHestonEngine::Gatheral;
const AnalyticHestonEngine* const hestonEnginePtr = 0;
Real npv;
Size evaluations;
AnalyticHestonEngine::doCalculation(
df, div, spotPrice, strike, t,
kappa, theta, sigma, v0, rho,
payoff, integration_, cpxLogFormula,
hestonEnginePtr, npv, evaluations);
if (npv <= 0.0) return std::sqrt(theta);
Brent solver;
solver.setMaxEvaluations(10000);
const Volatility guess = std::sqrt(theta);
const Real accuracy = std::numeric_limits<Real>::epsilon();
const boost::function<Real(Real)> f = boost::bind(
&blackValue, payoff.optionType(), strike, fwd, t, _1, df, npv);
return solver.solve(f, accuracy, guess, 0.01);
}
Real InverseNonCentralChiSquareDistribution::operator()(Real x) const {
// first find the right side of the interval
Real upper = guess_;
Size evaluations = maxEvaluations_;
while (nonCentralDist_(upper) < x && evaluations > 0) {
upper*=2.0;
--evaluations;
}
// use a brent solver for the rest
Brent solver;
solver.setMaxEvaluations(evaluations);
return solver.solve(compose(std::bind2nd(std::minus<Real>(),x),
nonCentralDist_),
accuracy_, 0.75*upper,
(evaluations == maxEvaluations_)? 0.0: 0.5*upper,
upper);
}
Volatility CdsOption::impliedVolatility(
Real targetValue,
const Handle<YieldTermStructure>& termStructure,
const Handle<DefaultProbabilityTermStructure>& probability,
Real recoveryRate,
Real accuracy,
Size maxEvaluations,
Volatility minVol,
Volatility maxVol) const {
calculate();
QL_REQUIRE(!isExpired(), "instrument expired");
Volatility guess = 0.10;
ImpliedVolHelper f(*this, probability, recoveryRate,
termStructure, targetValue);
Brent solver;
solver.setMaxEvaluations(maxEvaluations);
return solver.solve(f, accuracy, guess, minVol, maxVol);
}
Volatility ImpliedVolatilityHelper::calculate(
const Instrument& instrument,
const PricingEngine& engine,
SimpleQuote& volQuote,
Real targetValue,
Real accuracy,
Natural maxEvaluations,
Volatility minVol,
Volatility maxVol) {
instrument.setupArguments(engine.getArguments());
engine.getArguments()->validate();
PriceError f(engine, volQuote, targetValue);
Brent solver;
solver.setMaxEvaluations(maxEvaluations);
Volatility guess = (minVol+maxVol)/2.0;
Volatility result = solver.solve(f, accuracy, guess,
minVol, maxVol);
return result;
}
Real CmsSpreadOption::impliedCorrelation(boost::shared_ptr<CmsPricer> pricer,const Period& pillar, const double price,Size preCalculatedFixings,double preCalculatedPrice) {
Brent b;
double res=b.solve(CmsSpreadOptionImplCorrHelper(this,pricer,pillar,price,preCalculatedFixings,preCalculatedPrice),CORRACC,pricer->correlationTermStructure()->correlation(pillar,true),CORRSTEP);
double res2=atan(res)*2.0/M_PI;
pricer->correlationTermStructure()->setPillarCorrelation(pillar,res2);
return res2;
/*CmsSpreadOptionImplCorrHelper h(boost::shared_ptr<CmsSpreadOption>(this),pricer,pillar,price);
double x1=-MAXCORR,x2=MAXCORR,x;
double f1=h(x1);
double f2=h(x2);
double f;
double step=MAXCORR+MAXCORR;
if(f1*f2>=0.0) QL_FAIL("No sign change for correlations -1,1");
do {
x=(x1+x2)/2.0;
f=h(x);
if(f1*f<0.0) x2=x; else x1=x;
step/=step;
pricer->correlationTermStructure()->setPillarCorrelation(pillar,x);
} while(step>CORRACC);
pricer->correlationTermStructure()->setPillarCorrelation(pillar,x);
return x;*/
}
void IterativeBootstrap<Curve>::calculate() const {
Size n = ts_->instruments_.size();
// ensure rate helpers are sorted
std::sort(ts_->instruments_.begin(), ts_->instruments_.end(),
detail::BootstrapHelperSorter());
// check that there is no instruments with the same maturity
for (Size i=1; i<n; ++i) {
Date m1 = ts_->instruments_[i-1]->latestDate(),
m2 = ts_->instruments_[i]->latestDate();
QL_REQUIRE(m1 != m2,
"two instruments have the same maturity ("<< m1 <<")");
}
// check that there is no instruments with invalid quote
for (Size i=0; i<n; ++i)
QL_REQUIRE(ts_->instruments_[i]->quote()->isValid(),
io::ordinal(i+1) << " instrument (maturity: " <<
ts_->instruments_[i]->latestDate() <<
") has an invalid quote");
// setup instruments
for (Size i=0; i<n; ++i) {
// don't try this at home!
// This call creates instruments, and removes "const".
// There is a significant interaction with observability.
ts_->instruments_[i]->setTermStructure(const_cast<Curve*>(ts_));
}
// calculate dates and times
ts_->dates_ = std::vector<Date>(n+1);
ts_->times_ = std::vector<Time>(n+1);
ts_->dates_[0] = Traits::initialDate(ts_);
ts_->times_[0] = ts_->timeFromReference(ts_->dates_[0]);
for (Size i=0; i<n; ++i) {
ts_->dates_[i+1] = ts_->instruments_[i]->latestDate();
ts_->times_[i+1] = ts_->timeFromReference(ts_->dates_[i+1]);
}
// set initial guess only if the current curve cannot be used as guess
if (validCurve_) {
QL_ENSURE(ts_->data_.size() == n+1,
"dimension mismatch: expected " << n+1 <<
", actual " << ts_->data_.size());
} else {
ts_->data_ = std::vector<Rate>(n+1);
ts_->data_[0] = Traits::initialValue(ts_);
for (Size i=0; i<n; ++i)
ts_->data_[i+1] = Traits::initialGuess();
}
Brent solver;
Size maxIterations = Traits::maxIterations();
for (Size iteration=0; ; ++iteration) {
std::vector<Rate> previousData = ts_->data_;
// restart from the previous interpolation
if (validCurve_) {
ts_->interpolation_ = ts_->interpolator_.interpolate(
ts_->times_.begin(),
ts_->times_.end(),
ts_->data_.begin());
}
for (Size i=1; i<n+1; ++i) {
// calculate guess before extending interpolation
// to ensure that any extrapolation is performed
// using the curve bootstrapped so far and no more
boost::shared_ptr<typename Traits::helper> instrument =
ts_->instruments_[i-1];
Rate guess = 0.0;
if (validCurve_ || iteration>0) {
guess = ts_->data_[i];
} else if (i==1) {
guess = Traits::initialGuess();
} else {
// most traits extrapolate
guess = Traits::guess(ts_, ts_->dates_[i]);
}
// bracket
Real min = Traits::minValueAfter(i, ts_->data_);
Real max = Traits::maxValueAfter(i, ts_->data_);
if (guess<=min || guess>=max)
guess = (min+max)/2.0;
if (!validCurve_ && iteration == 0) {
// extend interpolation a point at a time
try {
ts_->interpolation_ = ts_->interpolator_.interpolate(
ts_->times_.begin(),
ts_->times_.begin()+i+1,
ts_->data_.begin());
} catch(...) {
if (!Interpolator::global)
throw; // no chance to fix it in a later iteration
// otherwise, if the target interpolation is
// not usable yet
ts_->interpolation_ = Linear().interpolate(
ts_->times_.begin(),
ts_->times_.begin()+i+1,
ts_->data_.begin());
}
}
// required because we just changed the data
// is it really required?
ts_->interpolation_.update();
try {
BootstrapError<Curve> error(ts_, instrument, i);
Real r = solver.solve(error,ts_->accuracy_,guess,min,max);
// redundant assignment (as it has been already performed
// by BootstrapError in solve procedure), but safe
ts_->data_[i] = r;
} catch (std::exception &e) {
validCurve_ = false;
QL_FAIL(io::ordinal(iteration+1) << " iteration: "
"failed at " << io::ordinal(i) << " instrument"
", maturity " << ts_->dates_[i] <<
", reference date " << ts_->dates_[0] <<
": " << e.what());
}
}
if (!Interpolator::global)
break; // no need for convergence loop
else if (!validCurve_ && iteration == 0) {
// ensure the target interpolation is used
ts_->interpolation_ =
ts_->interpolator_.interpolate(ts_->times_.begin(),
ts_->times_.end(),
ts_->data_.begin());
// at least one more iteration is needed to check convergence
continue;
}
// exit conditions
Real improvement = 0.0;
for (Size i=1; i<n+1; ++i)
improvement=std::max(improvement,
std::fabs(ts_->data_[i]-previousData[i]));
if (improvement<=ts_->accuracy_) // convergence reached
break;
QL_REQUIRE(iteration+1 < maxIterations,
"convergence not reached after " <<
iteration+1 << " iterations; last improvement " <<
improvement << ", required accuracy " <<
ts_->accuracy_);
}
validCurve_ = true;
}
void InterpolatedYoYOptionletStripper<Interpolator1D>::
initialize(const boost::shared_ptr<YoYCapFloorTermPriceSurface> &s,
const boost::shared_ptr<YoYInflationCapFloorEngine> &p,
const Real slope) const {
YoYCapFloorTermPriceSurface_ = s;
p_ = p;
lag_ = YoYCapFloorTermPriceSurface_->observationLag();
frequency_ = YoYCapFloorTermPriceSurface_->frequency();
indexIsInterpolated_ = YoYCapFloorTermPriceSurface_->indexIsInterpolated();
Natural fixingDays_ = YoYCapFloorTermPriceSurface_->fixingDays();
Natural settlementDays = 0; // always
Calendar cal = YoYCapFloorTermPriceSurface_->calendar();
BusinessDayConvention bdc =
YoYCapFloorTermPriceSurface_->businessDayConvention();
DayCounter dc = YoYCapFloorTermPriceSurface_->dayCounter();
// switch from caps to floors when out of floors
Rate maxFloor = YoYCapFloorTermPriceSurface_->floorStrikes().back();
YoYInflationCapFloor::Type useType = YoYInflationCapFloor::Floor;
Period TPmin = YoYCapFloorTermPriceSurface_->maturities().front();
// create a "fake index" based on Generic, this should work
// provided that the lag and frequency are correct
RelinkableHandle<YoYInflationTermStructure> hYoY(
YoYCapFloorTermPriceSurface_->YoYTS());
boost::shared_ptr<YoYInflationIndex> anIndex(
new YYGenericCPI(frequency_, false,
false, lag_,
Currency(), hYoY));
// strip each K separatly
for (Size i=0; i<YoYCapFloorTermPriceSurface_->strikes().size(); i++) {
Rate K = YoYCapFloorTermPriceSurface_->strikes()[i];
if (K > maxFloor) useType = YoYInflationCapFloor::Cap;
// solve for the initial point on the vol curve
Brent solver;
Real solverTolerance_ = 1e-7;
// these are VOLATILITY guesses (always +)
Real lo = 0.00001, hi = 0.08;
Real guess = (hi+lo)/2.0;
Real found;
Real priceToMatch =
(useType == YoYInflationCapFloor::Cap ?
YoYCapFloorTermPriceSurface_->capPrice(TPmin, K) :
YoYCapFloorTermPriceSurface_->floorPrice(TPmin, K));
try{
found = solver.solve(
ObjectiveFunction(useType, slope, K, lag_, fixingDays_,
anIndex, YoYCapFloorTermPriceSurface_,
p_, priceToMatch),
solverTolerance_, guess, lo, hi );
} catch( std::exception &e) {
QL_FAIL("failed to find solution here because: " << e.what());
}
// ***create helpers***
Real notional = 10000; // work in bps
std::vector<boost::shared_ptr<BootstrapHelper<YoYOptionletVolatilitySurface> > > helperInstruments;
std::vector<boost::shared_ptr<YoYOptionletHelper> > helpers;
for (Size j = 0; j < YoYCapFloorTermPriceSurface_->maturities().size(); j++){
Period Tp = YoYCapFloorTermPriceSurface_->maturities()[j];
Real nextPrice =
(useType == YoYInflationCapFloor::Cap ?
YoYCapFloorTermPriceSurface_->capPrice(Tp, K) :
YoYCapFloorTermPriceSurface_->floorPrice(Tp, K));
Handle<Quote> quote1(boost::shared_ptr<Quote>(
new SimpleQuote( nextPrice )));
// helper should be an integer number of periods away,
// this is enforced by rounding
Size nT = (Size)floor(s->timeFromReference(s->yoyOptionDateFromTenor(Tp))+0.5);
helpers.push_back(boost::shared_ptr<YoYOptionletHelper>(
new YoYOptionletHelper(quote1, notional, useType,
lag_,
dc, cal,
fixingDays_,
anIndex, K, nT, p_)));
boost::shared_ptr<ConstantYoYOptionletVolatility> yoyVolBLACK(
new ConstantYoYOptionletVolatility(found, settlementDays,
cal, bdc, dc,
lag_, frequency_,
false,
// -100% to +300%
-1.0,3.0));
helpers[j]->setTermStructure(
// gets underlying pointer & removes const
const_cast<ConstantYoYOptionletVolatility*>(
yoyVolBLACK.get()));
helperInstruments.push_back(helpers[j]);
}
// ***bootstrap***
// this is the artificial vol at zero so that first section works
Real Tmin = s->timeFromReference(s->yoyOptionDateFromTenor(TPmin));
Volatility baseYoYVolatility = found - slope * Tmin * found;
Rate eps = std::max(K, 0.02) / 1000.0;
Rate minStrike = K-eps;
Rate maxStrike = K+eps;
boost::shared_ptr<
PiecewiseYoYOptionletVolatilityCurve<Interpolator1D> > testPW(
new PiecewiseYoYOptionletVolatilityCurve<Interpolator1D>(
settlementDays, cal, bdc, dc, lag_,
frequency_, indexIsInterpolated_,
minStrike, maxStrike,
baseYoYVolatility,
helperInstruments) );
testPW->recalculate();
volCurves_.push_back(testPW);
}
}
NoArbSabrModel::NoArbSabrModel(const Real expiryTime, const Real forward,
const Real alpha, const Real beta, const Real nu,
const Real rho)
: expiryTime_(expiryTime), externalForward_(forward), alpha_(alpha),
beta_(beta), nu_(nu), rho_(rho), forward_(forward),
numericalForward_(forward) {
using namespace ext::placeholders;
QL_REQUIRE(expiryTime > 0.0 && expiryTime <= detail::NoArbSabrModel::expiryTime_max,
"expiryTime (" << expiryTime << ") out of bounds");
QL_REQUIRE(forward > 0.0, "forward (" << forward << ") must be positive");
QL_REQUIRE(beta >= detail::NoArbSabrModel::beta_min && beta <= detail::NoArbSabrModel::beta_max,
"beta (" << beta << ") out of bounds");
Real sigmaI = alpha * std::pow(forward, beta - 1.0);
QL_REQUIRE(sigmaI >= detail::NoArbSabrModel::sigmaI_min &&
sigmaI <= detail::NoArbSabrModel::sigmaI_max,
"sigmaI = alpha*forward^(beta-1.0) ("
<< sigmaI << ") out of bounds, alpha=" << alpha
<< " beta=" << beta << " forward=" << forward);
QL_REQUIRE(nu >= detail::NoArbSabrModel::nu_min && nu <= detail::NoArbSabrModel::nu_max,
"nu (" << nu << ") out of bounds");
QL_REQUIRE(rho >= detail::NoArbSabrModel::rho_min && rho <= detail::NoArbSabrModel::rho_max,
"rho (" << rho << ") out of bounds");
// determine a region sufficient for integration in the normal case
fmin_ = fmax_ = forward_;
for (Real tmp = p(fmax_);
tmp > std::max(detail::NoArbSabrModel::i_accuracy / std::max(1.0, fmax_ - fmin_),
detail::NoArbSabrModel::density_threshold);
tmp = p(fmax_)) {
fmax_ *= 2.0;
}
for (Real tmp = p(fmin_);
tmp > std::max(detail::NoArbSabrModel::i_accuracy / std::max(1.0, fmax_ - fmin_),
detail::NoArbSabrModel::density_threshold);
tmp = p(fmin_)) {
fmin_ *= 0.5;
}
fmin_ = std::max(detail::NoArbSabrModel::strike_min, fmin_);
QL_REQUIRE(fmax_ > fmin_, "could not find a reasonable integration domain");
integrator_ =
ext::make_shared<GaussLobattoIntegral>(
detail::NoArbSabrModel::i_max_iterations, detail::NoArbSabrModel::i_accuracy);
detail::D0Interpolator d0(forward_, expiryTime_, alpha_, beta_, nu_, rho_);
absProb_ = d0();
try {
Brent b;
Real start = std::sqrt(externalForward_ - detail::NoArbSabrModel::strike_min);
Real tmp =
b.solve(ext::bind(&NoArbSabrModel::forwardError, this, _1),
detail::NoArbSabrModel::forward_accuracy, start,
std::min(detail::NoArbSabrModel::forward_search_step, start / 2.0));
forward_ = tmp * tmp + detail::NoArbSabrModel::strike_min;
} catch (Error&) {
// fall back to unadjusted forward
forward_ = externalForward_;
}
Real d = forwardError(std::sqrt(forward_ - detail::NoArbSabrModel::strike_min));
numericalForward_ = d + externalForward_;
}
void KahaleSmileSection::compute() {
std::pair<Size,Size> afIdx = ssutils_->arbitragefreeIndices();
leftIndex_ = afIdx.first;
rightIndex_ = afIdx.second;
if(deleteArbitragePoints_) {
while(leftIndex_>1 || rightIndex_<k_.size()-1) {
ssutils_ = boost::shared_ptr<SmileSectionUtils>(new SmileSectionUtils(*source_,moneynessGrid_,f_));
std::pair<Size,Size> afIdx = ssutils_->arbitragefreeIndices();
leftIndex_ = afIdx.first;
rightIndex_ = afIdx.second;
QL_REQUIRE(rightIndex_>leftIndex_,
"arbitrage free region must at least contain two points (only index is " << leftIndex_ << ")");
if(leftIndex_>1) {
moneynessGrid_.erase(moneynessGrid_.begin()+leftIndex_-1);
k_.erase(k_.begin()+leftIndex_-1);
c_.erase(c_.begin()+leftIndex_-1);
leftIndex_--;
rightIndex_--;
}
if(rightIndex_<k_.size()-1) {
moneynessGrid_.erase(moneynessGrid_.begin()+rightIndex_+1);
k_.erase(k_.begin()+rightIndex_+1);
c_.erase(c_.begin()+rightIndex_+1);
rightIndex_--;
}
}
}
cFunctions_ = std::vector<boost::shared_ptr<cFunction> >(rightIndex_-leftIndex_+2);
// extrapolation in the leftmost interval
Brent brent;
bool success;
Real secl = 0.0;
do {
success=true;
try {
Real k1 = k_[leftIndex_];
Real c1 = c_[leftIndex_];
Real c0 = c_[0];
secl = (c_[leftIndex_]-c_[0]) / (k_[leftIndex_]-k_[0]);
Real sec = (c_[leftIndex_+1]-c_[leftIndex_]) / (k_[leftIndex_+1]-k_[leftIndex_]);
Real c1p;
if(interpolate_) c1p=(secl+sec)/2;
else {
c1p=(blackFormula(Option::Call, k1+gap_, f_, sqrt(source_->variance(k1+gap_)))-
blackFormula(Option::Call, k1, f_, sqrt(source_->variance(k1))))/gap_;
QL_REQUIRE(secl < c1p && c1p <= 0.0,"dummy");
// can not extrapolate so throw exception which is caught below
}
sHelper1 sh1(k1,c0,c1,c1p);
Real s = brent.solve(sh1,QL_KAHALE_ACC,0.20,0.00,QL_KAHALE_SMAX); // numerical parameters hardcoded here
sh1(s);
boost::shared_ptr<cFunction> cFct1(new cFunction(sh1.f_,s,0.0,sh1.b_));
cFunctions_[0]=cFct1;
} catch(...) {
leftIndex_++;
success=false;
}
} while(!success && leftIndex_ < rightIndex_);
QL_REQUIRE(leftIndex_ < rightIndex_, "can not extrapolate to left, right index of af region reached ("
<< rightIndex_ << ")");
// interpolation
Real cp0 = 0.0, cp1 = 0.0;
if(interpolate_) {
for(Size i = leftIndex_; i<rightIndex_; i++) {
Real k0 = k_[i];
Real k1 = k_[i+1];
Real c0 = c_[i];
Real c1 = c_[i+1];
Real sec = (c_[i+1]-c_[i]) / (k_[i+1]-k_[i]);
if(i==leftIndex_) cp0 = leftIndex_ > 0 ? (secl + sec) / 2.0 : sec;
Real secr;
if(i==rightIndex_-1) secr=0.0;
else secr = (c_[i+2]-c_[i+1]) / (k_[i+2]-k_[i+1]);
cp1 = (sec+secr) / 2.0;
aHelper ah(k0,k1,c0,c1,cp0,cp1);
Real a;
try {
a = brent.solve(ah,QL_KAHALE_ACC,0.5*(cp1+(1.0+cp0)),cp1+QL_KAHALE_EPS,1.0+cp0-QL_KAHALE_EPS);
// numerical parameters hardcoded here
} catch(...) {
// from theory there must exist a zero. if the solver does not find it, it most
// probably lies close one of the interval bounds. Just choose the better bound
// and relax the accuracy. This does not matter in practice usually.
Real la = std::fabs(ah(cp1+QL_KAHALE_EPS));
Real ra = std::fabs(ah(1.0+cp0-QL_KAHALE_EPS));
if( la < QL_KAHALE_ACC_RELAX || ra < QL_KAHALE_ACC_RELAX) { // tolerance hardcoded here
a = la < ra ? cp1+QL_KAHALE_EPS : 1.0+cp0-QL_KAHALE_EPS;
}
else
QL_FAIL("can not interpolate at index " << i);
}
ah(a);
boost::shared_ptr<cFunction> cFct(new cFunction(ah.f_,ah.s_,a,ah.b_));
cFunctions_[leftIndex_ > 0 ? i-leftIndex_+1 : 0]=cFct;
cp0=cp1;
}
}
// extrapolation of right wing
do {
success=true;
try {
Real k0 = k_[rightIndex_];
Real c0 = c_[rightIndex_];
Real cp0;
if(interpolate_) cp0 = 0.5*(c_[rightIndex_]-c_[rightIndex_-1])/(k_[rightIndex_]-k_[rightIndex_-1]);
else {
cp0=(blackFormula(Option::Call, k0, f_, sqrt(source_->variance(k0)))-
blackFormula(Option::Call, k0-gap_, f_, sqrt(source_->variance(k0-gap_))))/gap_;
}
boost::shared_ptr<cFunction> cFct;
if(exponentialExtrapolation_) {
cFct = boost::shared_ptr<cFunction>(new cFunction(-cp0/c0 ,std::log(c0)-cp0/c0*k0));
}
else {
sHelper sh(k0,c0,cp0);
Real s;
s = brent.solve(sh,QL_KAHALE_ACC,0.20,0.0,QL_KAHALE_SMAX); // numerical parameters hardcoded here
sh(s);
cFct = boost::shared_ptr<cFunction>(new cFunction(sh.f_,s,0.0,0.0));
}
cFunctions_[rightIndex_-leftIndex_+1]=cFct;
} catch (...) {
rightIndex_--;
success=false;
}
} while(!success && rightIndex_ > leftIndex_);
QL_REQUIRE(leftIndex_ < rightIndex_, "can not extrapolate to right, left index of af region reached (" <<
leftIndex_ << ")");
}
CapPseudoDerivative::CapPseudoDerivative(boost::shared_ptr<MarketModel> inputModel,
Real strike,
Size startIndex,
Size endIndex, Real firstDF) : firstDF_(firstDF)
{
QL_REQUIRE(startIndex < endIndex, "for a cap pseudo derivative the start of the cap must be before the end");
QL_REQUIRE( endIndex <= inputModel->numberOfRates(), "for a cap pseudo derivative the end of the cap must before the end of the rates");
Size numberCaplets = endIndex-startIndex;
Size numberRates = inputModel->numberOfRates();
Size factors = inputModel->numberOfFactors();
LMMCurveState curve(inputModel->evolution().rateTimes());
curve.setOnForwardRates(inputModel->initialRates());
const Matrix& totalCovariance(inputModel->totalCovariance(inputModel->numberOfSteps()-1));
std::vector<Real> displacedImpliedVols(numberCaplets);
std::vector<Real> annuities(numberCaplets);
std::vector<Real> initialRates(numberCaplets);
std::vector<Real> expiries(numberCaplets);
Real capPrice =0.0;
Real guess=0.0;
Real minVol = 1e10;
Real maxVol =0.0;
for (Size j = startIndex; j < endIndex; ++j)
{
Size capletIndex = j - startIndex;
Time resetTime = inputModel->evolution().rateTimes()[j];
expiries[capletIndex] = resetTime;
Real sd = std::sqrt(totalCovariance[j][j]);
displacedImpliedVols[capletIndex] = std::sqrt(totalCovariance[j][j]/resetTime);
Real forward = inputModel->initialRates()[j];
initialRates[capletIndex] = forward;
Real annuity = curve.discountRatio(j+1,0)* inputModel->evolution().rateTaus()[j]*firstDF_;
annuities[capletIndex] = annuity;
Real displacement = inputModel->displacements()[j];
guess+= displacedImpliedVols[capletIndex]*(forward+displacement)/forward;
minVol =std::min(minVol, displacedImpliedVols[capletIndex]);
maxVol =std::max(maxVol, displacedImpliedVols[capletIndex]*(forward+displacement)/forward);
Real capletPrice = blackFormula(Option::Call,
strike,
forward,
sd,
annuity,
displacement
);
capPrice += capletPrice;
}
guess/=numberCaplets;
for (Size step =0; step < inputModel->evolution().numberOfSteps(); ++step)
{
Matrix thisDerivative(numberRates,factors,0.0);
for (Size rate =std::max(inputModel->evolution().firstAliveRate()[step],startIndex);
rate < endIndex; ++rate)
{
for (Size f=0; f < factors; ++f)
{
Real expiry = inputModel->evolution().rateTimes()[rate];
Real volDerivative = inputModel->pseudoRoot(step)[rate][f]
/(displacedImpliedVols[rate-startIndex]*expiry);
Real capletVega = blackFormulaVolDerivative(strike,inputModel->initialRates()[rate],
displacedImpliedVols[rate-startIndex]*std::sqrt(expiry),
expiry,
annuities[rate-startIndex],
inputModel->displacements()[rate]);
// note that the cap derivative is equal to one of the caplet ones so we lose a loop
thisDerivative[rate][f] = volDerivative*capletVega;
}
}
priceDerivatives_.push_back(thisDerivative);
}
QuickCap capPricer(strike, annuities, initialRates, expiries,capPrice);
Size maxEvaluations = 1000;
Real accuracy = 1E-6;
Brent solver;
solver.setMaxEvaluations(maxEvaluations);
impliedVolatility_ = solver.solve(capPricer,accuracy,guess,minVol*0.99,maxVol*1.01);
vega_ = capPricer.vega(impliedVolatility_);
for (Size step =0; step < inputModel->evolution().numberOfSteps(); ++step)
{
Matrix thisDerivative(numberRates,factors,0.0);
for (Size rate =std::max(inputModel->evolution().firstAliveRate()[step],startIndex);
rate < endIndex; ++rate)
{
for (Size f=0; f < factors; ++f)
{
thisDerivative[rate][f] = priceDerivatives_[step][rate][f]/vega_;
}
}
volatilityDerivatives_.push_back(thisDerivative);
}
}
void AnalyticCompoundOptionEngine::calculate() const {
QL_REQUIRE(strikeDaughter()>0.0,
"Daughter strike must be positive");
QL_REQUIRE(strikeMother()>0.0,
"Mother strike must be positive");
QL_REQUIRE(spot() >= 0.0, "negative or null underlying given");
/* Solver Setup ***************************************************/
Date helpDate(process_->riskFreeRate()->referenceDate());
Date helpMaturity=helpDate+(maturityDaughter()-maturityMother())*Days;
Real vol =process_->blackVolatility()->blackVol(helpMaturity,
strikeDaughter());
Time helpTimeToMat=process_->time(helpMaturity);
vol=vol*std::sqrt(helpTimeToMat);
DiscountFactor dividendDiscount =
process_->dividendYield()->discount(helpMaturity);
DiscountFactor riskFreeDiscount =
process_->riskFreeRate()->discount(helpMaturity);
boost::shared_ptr<ImpliedSpotHelper> f(
new ImpliedSpotHelper(dividendDiscount, riskFreeDiscount,
vol, payoffDaughter(), strikeMother()));
Brent solver;
solver.setMaxEvaluations(1000);
Real accuracy = 1.0e-6;
Real X=0.0;
Real sSolved=0.0;
sSolved=solver.solve(*f, accuracy, strikeDaughter(), 1.0e-6, strikeDaughter()*1000.0);
X=transformX(sSolved); // transform stock to return as in Wystup's book
/* Solver Setup Finished*****************************************/
Real phi=typeDaughter(); // -1 or 1
Real w=typeMother(); // -1 or 1
Real rho=std::sqrt(residualTimeMother()/residualTimeDaughter());
BivariateCumulativeNormalDistributionDr78 N2(w*rho) ;
DiscountFactor ddD=dividendDiscountDaughter();
DiscountFactor rdD=riskFreeDiscountDaughter();
//DiscountFactor ddM=dividendDiscountMother();
DiscountFactor rdM=riskFreeDiscountMother();
Real XmSM=X-stdDeviationMother();
Real S=spot();
Real dP=dPlus();
Real dPT12=dPlusTau12(sSolved);
Real vD=volatilityDaughter();
Real dM=dMinus();
Real strD=strikeDaughter();
Real strM=strikeMother();
Real rTM=residualTimeMother();
Real rTD=residualTimeDaughter();
Real rD=riskFreeRateDaughter();
Real dD=dividendRateDaughter();
Real tempRes=0.0;
Real tempDelta=0.0;
Real tempGamma=0.0;
Real tempVega=0.0;
Real tempTheta=0.0;
Real N2XmSM=N2(-phi*w*XmSM,phi*dP);
Real N2X=N2(-phi*w*X,phi*dM);
Real NeX=N_(-phi*w*e(X));
Real NX=N_(-phi*w*X);
Real NT12=N_(phi*dPT12);
Real ndP=n_(dP);
Real nXm=n_(XmSM);
Real invMTime=1/std::sqrt(rTM);
Real invDTime=1/std::sqrt(rTD);
tempRes=phi*w*S*ddD*N2XmSM-phi*w*strD*rdD*N2X-w*strM*rdM*NX;
tempDelta=phi*w*ddD*N2XmSM;
tempGamma=(ddD/(vD*S))*(invMTime*nXm*NT12+w*invDTime*ndP*NeX);
tempVega=ddD*S*((1/invMTime)*nXm*NT12+w*(1/invDTime)*ndP*NeX);
tempTheta+=phi*w*dD*S*ddD*N2XmSM-phi*w*rD*strD*rdD*N2X-w*rD*strM*rdM*NX;
tempTheta-=0.5*vD*S*ddD*(invMTime*nXm*NT12+w*invDTime*ndP*NeX);
results_.value=tempRes;
results_.delta=tempDelta;
results_.gamma=tempGamma;
results_.vega=tempVega;
results_.theta=tempTheta;
}
void KahaleSmileSection::compute() {
std::pair<Size, Size> afIdx = ssutils_->arbitragefreeIndices();
leftIndex_ = afIdx.first;
rightIndex_ = afIdx.second;
cFunctions_ = std::vector<boost::shared_ptr<cFunction> >(
rightIndex_ - leftIndex_ + 2);
// extrapolation in the leftmost interval
Brent brent;
bool success;
Real secl = 0.0;
do {
success = true;
try {
Real k1 = k_[leftIndex_];
Real c1 = c_[leftIndex_];
Real c0 = c_[0];
secl = (c_[leftIndex_] - c_[0]) / (k_[leftIndex_] - k_[0]);
Real sec = (c_[leftIndex_ + 1] - c_[leftIndex_]) /
(k_[leftIndex_ + 1] - k_[leftIndex_]);
Real c1p;
if (interpolate_)
c1p = (secl + sec) / 2;
else {
c1p = (blackFormula(Option::Call, k1 + gap_, f_,
sqrt(source_->variance(k1 + gap_))) -
blackFormula(Option::Call, k1, f_,
sqrt(source_->variance(k1)))) /
gap_;
QL_REQUIRE(secl < c1p && c1p <= 0.0, "dummy");
// can not extrapolate so throw exception which is caught
// below
}
sHelper1 sh1(k1, c0, c1, c1p);
Real s = brent.solve(sh1, QL_KAHALE_ACC, 0.20, 0.00,
QL_KAHALE_SMAX); // numerical parameters
// hardcoded here
sh1(s);
boost::shared_ptr<cFunction> cFct1(
new cFunction(sh1.f_, s, 0.0, sh1.b_));
cFunctions_[0] = cFct1;
// sanity check - in rare cases we can get digitials
// which are not monotonic or greater than 1.0
// due to numerical effects. Move to the next index in
// these cases.
Real dig = digitalOptionPrice(k1 / 2.0);
QL_REQUIRE(dig >= -c1p && dig <= 1.0, "dummy");
}
catch (...) {
leftIndex_++;
success = false;
}
} while (!success && leftIndex_ < rightIndex_);
QL_REQUIRE(
leftIndex_ < rightIndex_,
"can not extrapolate to left, right index of af region reached ("
<< rightIndex_ << ")");
// interpolation
Real cp0 = 0.0, cp1 = 0.0;
if (interpolate_) {
for (Size i = leftIndex_; i < rightIndex_; i++) {
Real k0 = k_[i];
Real k1 = k_[i + 1];
Real c0 = c_[i];
Real c1 = c_[i + 1];
Real sec = (c_[i + 1] - c_[i]) / (k_[i + 1] - k_[i]);
if (i == leftIndex_)
cp0 = leftIndex_ > 0 ? (secl + sec) / 2.0 : sec;
Real secr;
if (i == rightIndex_ - 1)
secr = 0.0;
else
secr = (c_[i + 2] - c_[i + 1]) / (k_[i + 2] - k_[i + 1]);
cp1 = (sec + secr) / 2.0;
aHelper ah(k0, k1, c0, c1, cp0, cp1);
Real a;
bool valid = false;
try {
a = brent.solve(
ah, QL_KAHALE_ACC, 0.5 * (cp1 + (1.0 + cp0)),
cp1 + QL_KAHALE_EPS, 1.0 + cp0 - QL_KAHALE_EPS);
// numerical parameters hardcoded here
valid = true;
}
catch (...) {
// delete the right point of the interval where we try to
// interpolate
moneynessGrid_.erase(moneynessGrid_.begin() + (i + 1));
k_.erase(k_.begin() + (i + 1));
c_.erase(c_.begin() + (i + 1));
cFunctions_.erase(cFunctions_.begin() + (i + 1));
rightIndex_--;
i--;
}
if (valid) {
ah(a);
boost::shared_ptr<cFunction> cFct(
new cFunction(ah.f_, ah.s_, a, ah.b_));
cFunctions_[leftIndex_ > 0 ? i - leftIndex_ + 1 : 0] = cFct;
cp0 = cp1;
}
}
}
// extrapolation of right wing
do {
success = true;
try {
Real k0 = k_[rightIndex_];
Real c0 = c_[rightIndex_];
Real cp0;
if (interpolate_)
cp0 = 0.5 * (c_[rightIndex_] - c_[rightIndex_ - 1]) /
(k_[rightIndex_] - k_[rightIndex_ - 1]);
else {
cp0 = (blackFormula(Option::Call, k0, f_,
sqrt(source_->variance(k0))) -
blackFormula(Option::Call, k0 - gap_, f_,
sqrt(source_->variance(k0 - gap_)))) /
gap_;
}
boost::shared_ptr<cFunction> cFct;
if (exponentialExtrapolation_) {
QL_REQUIRE(-cp0 / c0 > 0.0, "dummy"); // this is caught
// below
cFct = boost::shared_ptr<cFunction>(
new cFunction(-cp0 / c0, std::log(c0) - cp0 / c0 * k0));
} else {
sHelper sh(k0, c0, cp0);
Real s;
s = brent.solve(sh, QL_KAHALE_ACC, 0.20, 0.0,
QL_KAHALE_SMAX); // numerical parameters
// hardcoded here
sh(s);
cFct = boost::shared_ptr<cFunction>(
new cFunction(sh.f_, s, 0.0, 0.0));
}
cFunctions_[rightIndex_ - leftIndex_ + 1] = cFct;
}
catch (...) {
rightIndex_--;
success = false;
}
} while (!success && rightIndex_ > leftIndex_);
QL_REQUIRE(
leftIndex_ < rightIndex_,
"can not extrapolate to right, left index of af region reached ("
<< leftIndex_ << ")");
}
