public double value(IPath path)
{
Utils.QL_REQUIRE(!(path as Path).empty(), () => "the path cannot be empty");
TimeGrid doubleGrid = (path as Path).timeGrid();
int startIndex = doubleGrid.closestIndex(lookbackStart_);
double underlying;
switch (payoff_.optionType())
{
case Option.Type.Put:
underlying = (path as Path).values().GetRange(startIndex, (path as Path).values().Count - startIndex).Min();
break;
case Option.Type.Call:
underlying = (path as Path).values().GetRange(startIndex, (path as Path).values().Count - startIndex).Max();
break;
default:
underlying = 0.0;
Utils.QL_FAIL("unknown option type");
break;
}
return(payoff_.value(underlying) * discount_);
}
protected override PathPricer <IPath> pathPricer()
{
TimeGrid grid = this.timeGrid();
double discount = (this.process_ as GeneralizedBlackScholesProcess)
.riskFreeRate().currentLink().discount(grid.Last());
ContinuousFixedLookbackOption.Arguments arg1 = this.arguments_ as ContinuousFixedLookbackOption.Arguments;
ContinuousPartialFixedLookbackOption.Arguments arg2 = this.arguments_ as ContinuousPartialFixedLookbackOption.Arguments;
ContinuousFloatingLookbackOption.Arguments arg3 = this.arguments_ as ContinuousFloatingLookbackOption.Arguments;
ContinuousPartialFloatingLookbackOption.Arguments arg4 = this.arguments_ as ContinuousPartialFloatingLookbackOption.Arguments;
if (arg2 != null)
{
return(mc_looback_path_pricer(arg2, this.process_ as GeneralizedBlackScholesProcess, discount));
}
else if (arg1 != null)
{
return(mc_looback_path_pricer(arg1, this.process_ as GeneralizedBlackScholesProcess, discount));
}
else if (arg4 != null)
{
return(mc_looback_path_pricer(arg4, this.process_ as GeneralizedBlackScholesProcess, discount));
}
else if (arg3 != null)
{
return(mc_looback_path_pricer(arg3, this.process_ as GeneralizedBlackScholesProcess, discount));
}
else
{
return(null);
}
}
public PiecewiseTimeDependentHestonModel(Handle <YieldTermStructure> riskFreeRate,
Handle <YieldTermStructure> dividendYield,
Handle <Quote> s0,
double v0,
Parameter theta,
Parameter kappa,
Parameter sigma,
Parameter rho,
TimeGrid timeGrid)
: base(5)
{
s0_ = s0;
riskFreeRate_ = riskFreeRate;
dividendYield_ = dividendYield;
timeGrid_ = timeGrid;
arguments_[0] = theta;
arguments_[1] = kappa;
arguments_[2] = sigma;
arguments_[3] = rho;
arguments_[4] = new ConstantParameter(v0, new PositiveConstraint());
s0.registerWith(update);
riskFreeRate.registerWith(update);
dividendYield.registerWith(update);
}
public override Lattice tree(TimeGrid grid)
{
TermStructureFittingParameter phi = new TermStructureFittingParameter(termStructure());
ShortRateDynamics numericDynamics = new Dynamics(phi, a(), sigma());
TrinomialTree trinomial = new TrinomialTree(numericDynamics.process(), grid);
ShortRateTree numericTree = new ShortRateTree(trinomial, numericDynamics, grid);
TermStructureFittingParameter.NumericalImpl impl =
(TermStructureFittingParameter.NumericalImpl)phi.implementation();
impl.reset();
for (int i = 0; i < (grid.size() - 1); i++)
{
double discountBond = termStructure().link.discount(grid[i + 1]);
Vector statePrices = numericTree.statePrices(i);
int size = numericTree.size(i);
double dt = numericTree.timeGrid().dt(i);
double dx = trinomial.dx(i);
double x = trinomial.underlying(i, 0);
double value = 0.0;
for (int j = 0; j < size; j++)
{
value += statePrices[j] * Math.Exp(-x * dt);
x += dx;
}
value = Math.Log(value / discountBond) / dt;
impl.setvalue(grid[i], value);
}
return(numericTree);
}
public override Lattice tree(TimeGrid grid)
{
TermStructureFittingParameter phi = new TermStructureFittingParameter(termStructure());
ShortRateDynamics numericDynamics =
new Dynamics(phi, a(), sigma());
TrinomialTree trinomial =
new TrinomialTree(numericDynamics.process(), grid);
ShortRateTree numericTree =
new ShortRateTree(trinomial, numericDynamics, grid);
TermStructureFittingParameter.NumericalImpl impl =
(TermStructureFittingParameter.NumericalImpl)phi.implementation();
impl.reset();
double value = 1.0;
double vMin = -50.0;
double vMax = 50.0;
for (int i = 0; i < (grid.size() - 1); i++)
{
double discountBond = termStructure().link.discount(grid[i + 1]);
double xMin = trinomial.underlying(i, 0);
double dx = trinomial.dx(i);
Helper finder = new Helper(i, xMin, dx, discountBond, numericTree);
Brent s1d = new Brent();
s1d.setMaxEvaluations(1000);
value = s1d.solve(finder, 1e-7, value, vMin, vMax);
impl.setvalue(grid[i], value);
}
return(numericTree);
}
protected override IPathGenerator <IRNG> pathGenerator()
{
TimeGrid grid = timeGrid();
IRNG gen = new RNG().make_sequence_generator(grid.size() - 1, seed_);
return(new PathGenerator <IRNG>(process_, grid, gen, brownianBridge_));
}
public double value(IPath path)
{
Utils.QL_REQUIRE(!(path as Path).empty(), () => "the path cannot be empty");
TimeGrid doubleGrid = (path as Path).timeGrid();
int endIndex = doubleGrid.closestIndex(lookbackEnd_);
double terminalPrice = (path as Path).back();
double strike;
switch (payoff_.optionType())
{
case Option.Type.Call:
strike = (path as Path).values().GetRange(0, endIndex).Min();
break;
case Option.Type.Put:
strike = (path as Path).values().GetRange(0, endIndex).Max();
break;
default:
strike = 0.0;
Utils.QL_FAIL("unknown option type");
break;
}
return(payoff_.value(terminalPrice, strike) * discount_);
}
public TreeLattice(TimeGrid timeGrid, int n) : base(timeGrid)
{
n_ = n;
Utils.QL_REQUIRE(n > 0, () => "there is no zeronomial lattice!");
statePrices_ = new InitializedList <Vector>(1, new Vector(1, 1.0));
statePricesLimit_ = 0;
}
public TreeCallableFixedRateBondEngine(ShortRateModel model, TimeGrid timeGrid,
Handle <YieldTermStructure> termStructure)
: base(model, timeGrid)
{
termStructure_ = termStructure;
termStructure_.registerWith(update);
}
public override Lattice tree(TimeGrid grid)
{
ShortRateDynamics dyn = dynamics();
TrinomialTree tree1 = new TrinomialTree(dyn.xProcess(), grid);
TrinomialTree tree2 = new TrinomialTree(dyn.yProcess(), grid);
return((Lattice)(new ShortRateTree(tree1, tree2, dyn)));
}
protected override IPathGenerator <IRNG> pathGenerator()
{
int dimensions = process_.factors();
TimeGrid grid = timeGrid();
IRNG generator = (IRNG)FastActivator <RNG> .Create().make_sequence_generator(dimensions * (grid.size() - 1), seed_);
return(new PathGenerator <IRNG>(process_, grid, generator, brownianBridge_));
}
//! Plain tree build-up from short-rate dynamics
public ShortRateTree(TrinomialTree tree,
ShortRateDynamics dynamics,
TimeGrid timeGrid)
: base(timeGrid, tree.size(1))
{
tree_ = tree;
dynamics_ = dynamics;
}
public TreeVanillaSwapEngine(ShortRateModel model,
TimeGrid timeGrid,
Handle <YieldTermStructure> termStructure)
: base(model, timeGrid)
{
termStructure_ = termStructure;
termStructure_.registerWith(update);
}
public MultiPath(int nAsset, TimeGrid timeGrid)
{
multiPath_ = new List <Path>(nAsset);
for (int i = 0; i < nAsset; i++)
{
multiPath_.Add(new Path(timeGrid));
}
Utils.QL_REQUIRE(nAsset > 0, () => "number of asset must be positive");
}
public LatticeShortRateModelEngine(ShortRateModel model,
TimeGrid timeGrid)
: base(model)
{
timeGrid_ = new TimeGrid(timeGrid.Last(), timeGrid.size() - 1 /*timeGrid.dt(1) - timeGrid.dt(0)*/);
timeGrid_ = timeGrid;
timeSteps_ = 0;
lattice_ = this.model_.link.tree(timeGrid);
}
public TrinomialTree(StochasticProcess1D process,
TimeGrid timeGrid,
bool isPositive /*= false*/)
: base(timeGrid.size())
{
branchings_ = new List <Branching>();
dx_ = new InitializedList <double>(1);
timeGrid_ = timeGrid;
x0_ = process.x0();
int nTimeSteps = timeGrid.size() - 1;
int jMin = 0;
int jMax = 0;
for (int i = 0; i < nTimeSteps; i++)
{
double t = timeGrid[i];
double dt = timeGrid.dt(i);
//Variance must be independent of x
double v2 = process.variance(t, 0.0, dt);
double v = Math.Sqrt(v2);
dx_.Add(v * Math.Sqrt(3.0));
Branching branching = new Branching();
for (int j = jMin; j <= jMax; j++)
{
double x = x0_ + j * dx_[i];
double m = process.expectation(t, x, dt);
int temp = (int)(Math.Floor((m - x0_) / dx_[i + 1] + 0.5));
if (isPositive)
{
while (x0_ + (temp - 1) * dx_[i + 1] <= 0)
{
temp++;
}
}
double e = m - (x0_ + temp * dx_[i + 1]);
double e2 = e * e;
double e3 = e * Math.Sqrt(3.0);
double p1 = (1.0 + e2 / v2 - e3 / v) / 6.0;
double p2 = (2.0 - e2 / v2) / 3.0;
double p3 = (1.0 + e2 / v2 + e3 / v) / 6.0;
branching.add(temp, p1, p2, p3);
}
branchings_.Add(branching);
jMin = branching.jMin();
jMax = branching.jMax();
}
}
private Sample <IPath> next(bool antithetic)
{
if (brownianBridge_)
{
Utils.QL_FAIL("Brownian bridge not supported");
return(null);
}
Sample <List <double> > sequence_ =
antithetic
? generator_.lastSequence()
: generator_.nextSequence();
int m = process_.size();
int n = process_.factors();
MultiPath path = (MultiPath)next_.value;
Vector asset = process_.initialValues();
for (int j = 0; j < m; j++)
{
path[j].setFront(asset[j]);
}
Vector temp;
next_.weight = sequence_.weight;
TimeGrid timeGrid = path[0].timeGrid();
double t, dt;
for (int i = 1; i < path.pathSize(); i++)
{
int offset = (i - 1) * n;
t = timeGrid[i - 1];
dt = timeGrid.dt(i - 1);
if (antithetic)
{
temp = -1 * new Vector(sequence_.value.GetRange(offset, n));
}
else
{
temp = new Vector(sequence_.value.GetRange(offset, n));
}
asset = process_.evolve(t, asset, dt, temp);
for (int j = 0; j < m; j++)
{
path[j][i] = asset[j];
}
}
return(next_);
}
public Path(TimeGrid timeGrid, Vector values)
{
timeGrid_ = timeGrid;
values_ = values.Clone();
if (values_.empty())
{
values_ = new Vector(timeGrid_.size());
}
Utils.QL_REQUIRE(values_.size() == timeGrid_.size(), () => "different number of times and asset values");
}
// constructors
public PathGenerator(StochasticProcess process, double length, int timeSteps, GSG generator, bool brownianBridge)
{
brownianBridge_ = brownianBridge;
generator_ = generator;
dimension_ = generator_.dimension();
timeGrid_ = new TimeGrid(length, timeSteps);
process_ = process as StochasticProcess1D;
next_ = new Sample <IPath>(new Path(timeGrid_), 1.0);
temp_ = new InitializedList <double>(dimension_);
bb_ = new BrownianBridge(timeGrid_);
Utils.QL_REQUIRE(dimension_ == timeSteps, () =>
"sequence generator dimensionality (" + dimension_ + ") != timeSteps (" + timeSteps + ")");
}
protected override IPathGenerator <IRNG> controlPathGenerator()
{
int dimensions = process_.factors();
TimeGrid grid = this.timeGrid();
IRNG generator = (IRNG) new RNG().make_sequence_generator(dimensions * (grid.size() - 1), this.seed_);
HybridHestonHullWhiteProcess process = process_ as HybridHestonHullWhiteProcess;
Utils.QL_REQUIRE(process != null, () => "invalid process");
HybridHestonHullWhiteProcess cvProcess = new HybridHestonHullWhiteProcess(process.hestonProcess(),
process.hullWhiteProcess(), 0.0, process.discretization());
return(new MultiPathGenerator <IRNG>(cvProcess, grid, generator, false));
}
public override void calculate()
{
if (base.model_ == null)
{
throw new ArgumentException("no model specified");
}
Date referenceDate;
DayCounter dayCounter;
ITermStructureConsistentModel tsmodel =
(ITermStructureConsistentModel)base.model_.link;
try
{
if (tsmodel != null)
{
referenceDate = tsmodel.termStructure().link.referenceDate();
dayCounter = tsmodel.termStructure().link.dayCounter();
}
else
{
referenceDate = termStructure_.link.referenceDate();
dayCounter = termStructure_.link.dayCounter();
}
}
catch
{
referenceDate = termStructure_.link.referenceDate();
dayCounter = termStructure_.link.dayCounter();
}
DiscretizedSwap swap = new DiscretizedSwap(arguments_, referenceDate, dayCounter);
List <double> times = swap.mandatoryTimes();
Lattice lattice;
if (lattice_ != null)
{
lattice = lattice_;
}
else
{
TimeGrid timeGrid = new TimeGrid(times, times.Count, timeSteps_);
lattice = model_.link.tree(timeGrid);
}
swap.initialize(lattice, times.Last());
swap.rollback(0.0);
results_.value = swap.presentValue();
}
public MultiPathGenerator(StochasticProcess process, TimeGrid times, GSG generator, bool brownianBridge)
{
brownianBridge_ = brownianBridge;
process_ = process;
generator_ = generator;
next_ = new Sample <IPath>(new MultiPath(process.size(), times), 1.0);
Utils.QL_REQUIRE(generator_.dimension() == process.factors() * (times.size() - 1), () =>
"dimension (" + generator_.dimension()
+ ") is not equal to ("
+ process.factors() + " * " + (times.size() - 1)
+ ") the number of factors "
+ "times the number of time steps");
Utils.QL_REQUIRE(times.size() > 1, () => "no times given");
}
public LongstaffSchwartzPathPricer(TimeGrid times, IEarlyExercisePathPricer <PathType, double> pathPricer,
YieldTermStructure termStructure)
{
calibrationPhase_ = true;
pathPricer_ = pathPricer;
coeff_ = new InitializedList <Vector>(times.size() - 1);
dF_ = new InitializedList <double>(times.size() - 1);
v_ = pathPricer_.basisSystem();
for (int i = 0; i < times.size() - 1; ++i)
{
dF_[i] = termStructure.discount(times[i + 1])
/ termStructure.discount(times[i]);
}
}
//! generic times
public BrownianBridge(TimeGrid timeGrid)
{
size_ = timeGrid.size() - 1;
t_ = new InitializedList <double>(size_);
sqrtdt_ = new InitializedList <double>(size_);
sqrtdt_ = new InitializedList <double>(size_);
bridgeIndex_ = new InitializedList <int>(size_);
leftIndex_ = new InitializedList <int>(size_);
rightIndex_ = new InitializedList <int>(size_);
leftWeight_ = new InitializedList <double>(size_);
rightWeight_ = new InitializedList <double>(size_);
stdDev_ = new InitializedList <double>(size_);
for (int i = 0; i < size_; ++i)
{
t_[i] = timeGrid[i + 1];
}
initialize();
}
//! Tree build-up + numerical fitting to term-structure
public ShortRateTree(TrinomialTree tree, ShortRateDynamics dynamics, TermStructureFittingParameter.NumericalImpl theta,
TimeGrid timeGrid)
: base(timeGrid, tree.size(1))
{
tree_ = tree;
dynamics_ = dynamics;
theta.reset();
double value = 1.0;
double vMin = -100.0;
double vMax = 100.0;
for (int i = 0; i < (timeGrid.size() - 1); i++)
{
double discountBond = theta.termStructure().link.discount(t_[i + 1]);
Helper finder = new Helper(i, discountBond, theta, this);
Brent s1d = new Brent();
s1d.setMaxEvaluations(1000);
value = s1d.solve(finder, 1e-7, value, vMin, vMax);
theta.change(value);
}
}
public override void calculate()
{
Utils.QL_REQUIRE(model_ != null, () => "no model specified");
Date referenceDate;
DayCounter dayCounter;
ITermStructureConsistentModel tsmodel = (ITermStructureConsistentModel)base.model_.link;
if (tsmodel != null)
{
referenceDate = tsmodel.termStructure().link.referenceDate();
dayCounter = tsmodel.termStructure().link.dayCounter();
}
else
{
referenceDate = termStructure_.link.referenceDate();
dayCounter = termStructure_.link.dayCounter();
}
DiscretizedCallableFixedRateBond callableBond = new DiscretizedCallableFixedRateBond(arguments_, referenceDate, dayCounter);
Lattice lattice;
if (lattice_ != null)
{
lattice = lattice_;
}
else
{
List <double> times = callableBond.mandatoryTimes();
TimeGrid timeGrid = new TimeGrid(times, times.Count, timeSteps_);
lattice = model_.link.tree(timeGrid);
}
double redemptionTime = dayCounter.yearFraction(referenceDate, arguments_.redemptionDate);
callableBond.initialize(lattice, redemptionTime);
callableBond.rollback(0.0);
results_.value = results_.settlementValue = callableBond.presentValue();
}
protected override PathPricer <IPath> pathPricer()
{
PlainVanillaPayoff payoff = arguments_.payoff as PlainVanillaPayoff;
Utils.QL_REQUIRE(payoff != null, () => "non-plain payoff given");
TimeGrid grid = timeGrid();
List <double> discounts = new InitializedList <double>(grid.size());
for (int i = 0; i < grid.size(); i++)
{
discounts[i] = process_.riskFreeRate().currentLink().discount(grid[i]);
}
// do this with template parameters?
if (isBiased_)
{
return(new BiasedBarrierPathPricer(arguments_.barrierType,
arguments_.barrier,
arguments_.rebate,
payoff.optionType(),
payoff.strike(),
discounts));
}
else
{
IRNG sequenceGen = new RandomSequenceGenerator <MersenneTwisterUniformRng>(grid.size() - 1, 5);
return(new BarrierPathPricer(arguments_.barrierType,
arguments_.barrier,
arguments_.rebate,
payoff.optionType(),
payoff.strike(),
discounts,
process_,
sequenceGen));
}
}
public override void calculate()
{
DayCounter rfdc = process_.riskFreeRate().link.dayCounter();
DayCounter divdc = process_.dividendYield().link.dayCounter();
DayCounter voldc = process_.blackVolatility().link.dayCounter();
Calendar volcal = process_.blackVolatility().link.calendar();
double s0 = process_.stateVariable().link.value();
Utils.QL_REQUIRE(s0 > 0.0, () => "negative or null underlying given");
double v = process_.blackVolatility().link.blackVol(arguments_.exercise.lastDate(), s0);
Date maturityDate = arguments_.exercise.lastDate();
double r = process_.riskFreeRate().link.zeroRate(maturityDate, rfdc, Compounding.Continuous, Frequency.NoFrequency).value();
double q = process_.dividendYield().link.zeroRate(maturityDate, divdc, Compounding.Continuous, Frequency.NoFrequency).value();
Date referenceDate = process_.riskFreeRate().link.referenceDate();
// binomial trees with constant coefficient
Handle <YieldTermStructure> flatRiskFree = new Handle <YieldTermStructure>(new FlatForward(referenceDate, r, rfdc));
Handle <YieldTermStructure> flatDividends = new Handle <YieldTermStructure>(new FlatForward(referenceDate, q, divdc));
Handle <BlackVolTermStructure> flatVol = new Handle <BlackVolTermStructure>(new BlackConstantVol(referenceDate, volcal, v, voldc));
StrikedTypePayoff payoff = arguments_.payoff as StrikedTypePayoff;
Utils.QL_REQUIRE(payoff != null, () => "non-striked payoff given");
double maturity = rfdc.yearFraction(referenceDate, maturityDate);
StochasticProcess1D bs = new GeneralizedBlackScholesProcess(process_.stateVariable(),
flatDividends, flatRiskFree, flatVol);
// correct timesteps to ensure a (local) minimum, using Boyle and Lau
// approach. See Journal of Derivatives, 1/1994,
// "Bumping up against the barrier with the binomial method"
// Note: this approach works only for CoxRossRubinstein lattices, so
// is disabled if T is not a CoxRossRubinstein or derived from it.
int optimum_steps = timeSteps_;
if (maxTimeSteps_ > timeSteps_ && s0 > 0 && arguments_.barrier > 0) // boost::is_base_of<CoxRossRubinstein, T>::value &&
{
double divisor;
if (s0 > arguments_.barrier)
{
divisor = Math.Pow(Math.Log(s0 / arguments_.barrier.Value), 2);
}
else
{
divisor = Math.Pow(Math.Log(arguments_.barrier.Value / s0), 2);
}
if (!Utils.close(divisor, 0))
{
for (int i = 1; i < timeSteps_; ++i)
{
int optimum = (int)((i * i * v * v * maturity) / divisor);
if (timeSteps_ < optimum)
{
optimum_steps = optimum;
break; // found first minimum with iterations>=timesteps
}
}
}
if (optimum_steps > maxTimeSteps_)
{
optimum_steps = maxTimeSteps_; // too high, limit
}
}
TimeGrid grid = new TimeGrid(maturity, optimum_steps);
ITree tree = getTree_(bs, maturity, optimum_steps, payoff.strike());
BlackScholesLattice <ITree> lattice = new BlackScholesLattice <ITree>(tree, r, maturity, optimum_steps);
DiscretizedAsset option = getAsset_(arguments_, process_, grid);
option.initialize(lattice, maturity);
// Partial derivatives calculated from various points in the
// binomial tree
// (see J.C.Hull, "Options, Futures and other derivatives", 6th edition, pp 397/398)
// Rollback to third-last step, and get underlying prices (s2) &
// option values (p2) at this point
option.rollback(grid[2]);
Vector va2 = new Vector(option.values());
Utils.QL_REQUIRE(va2.size() == 3, () => "Expect 3 nodes in grid at second step");
double p2u = va2[2]; // up
double p2m = va2[1]; // mid
double p2d = va2[0]; // down (low)
double s2u = lattice.underlying(2, 2); // up price
double s2m = lattice.underlying(2, 1); // middle price
double s2d = lattice.underlying(2, 0); // down (low) price
// calculate gamma by taking the first derivate of the two deltas
double delta2u = (p2u - p2m) / (s2u - s2m);
double delta2d = (p2m - p2d) / (s2m - s2d);
double gamma = (delta2u - delta2d) / ((s2u - s2d) / 2);
// Rollback to second-last step, and get option values (p1) at
// this point
option.rollback(grid[1]);
Vector va = new Vector(option.values());
Utils.QL_REQUIRE(va.size() == 2, () => "Expect 2 nodes in grid at first step");
double p1u = va[1];
double p1d = va[0];
double s1u = lattice.underlying(1, 1); // up (high) price
double s1d = lattice.underlying(1, 0); // down (low) price
double delta = (p1u - p1d) / (s1u - s1d);
// Finally, rollback to t=0
option.rollback(0.0);
double p0 = option.presentValue();
// Store results
results_.value = p0;
results_.delta = delta;
results_.gamma = gamma;
// theta can be approximated by calculating the numerical derivative
// between mid value at third-last step and at t0. The underlying price
// is the same, only time varies.
results_.theta = (p2m - p0) / grid[2];
}
public override Lattice tree(TimeGrid grid)
{
TrinomialTree trinomial = new TrinomialTree(dynamics().process(), grid, true);
return(new ShortRateTree(trinomial, dynamics(), grid));
}
public abstract Lattice tree(TimeGrid t);