protected double blackPrice(
final double spot,
final double strike,
final double expiry,
final double rate,
final double carry,
final double vol,
final boolean isCall) {
final Function1D<Double, Double> intCon = ICP.getEuropeanPayoff(strike, isCall);
final ConvectionDiffusionPDE1DStandardCoefficients pde =
PDE.getBlackScholes(rate, rate - carry, vol);
double sMin = 0.0;
double sMax = spot * Math.exp(_z * Math.sqrt(expiry));
BoundaryCondition lower;
BoundaryCondition upper;
if (isCall) {
lower = new DirichletBoundaryCondition(0.0, sMin);
Function1D<Double, Double> upperValue =
new Function1D<Double, Double>() {
@Override
public Double evaluate(Double tau) {
return Math.exp(-rate * tau) * (spot * Math.exp(carry * tau) - strike);
}
};
upper = new DirichletBoundaryCondition(upperValue, sMax);
} else {
Function1D<Double, Double> lowerValue =
new Function1D<Double, Double>() {
@Override
public Double evaluate(Double tau) {
return Math.exp(-rate * tau) * strike;
}
};
lower = new DirichletBoundaryCondition(lowerValue, sMin);
upper = new DirichletBoundaryCondition(0.0, sMax);
}
final MeshingFunction tMesh = new ExponentialMeshing(0, expiry, _nTNodes, _lambda);
final MeshingFunction xMesh = new HyperbolicMeshing(sMin, sMax, spot, _nXNodes, _bunching);
final PDEGrid1D grid = new PDEGrid1D(tMesh, xMesh);
PDE1DDataBundle<ConvectionDiffusionPDE1DCoefficients> pdeData =
new PDE1DDataBundle<ConvectionDiffusionPDE1DCoefficients>(pde, intCon, lower, upper, grid);
PDEResults1D res = SOLVER.solve(pdeData);
// for now just do linear interpolation on price. TODO replace this with something more robust
final double[] xNodes = grid.getSpaceNodes();
final int index = SurfaceArrayUtils.getLowerBoundIndex(xNodes, spot);
final double w = (xNodes[index + 1] - spot) / (xNodes[index + 1] - xNodes[index]);
return w * res.getFunctionValue(index) + (1 - w) * res.getFunctionValue(index + 1);
}
/**
* Computes the price of a one-touch out barrier option in the Black-Scholes world by solving the
* BS PDE on a finite difference grid. If a barrier is hit at any time before expiry, the option
* is cancelled (knocked-out) and a rebate (which is often zero) is paid <b>immediately</b>. If
* the barrier is not hit, then a normal European option payment is made.
*
* <p>If the barrier is above the spot it is assumed to be an up-and-out barrier (otherwise it
* would expire immediately) otherwise it is a down-and-out barrier As there are exact formulae
* for this case (see {@link BlackBarrierPriceFunction}), this is purely for testing purposes.
*
* @param spot The current (i.e. option price time) of the underlying
* @param barrierLevel The barrier level
* @param strike The strike of the European option
* @param expiry The expiry of the option
* @param rate The interest rate.
* @param carry The cost-of-carry (i.e. the forward = spot*exp(costOfCarry*T) )
* @param vol The Black volatility.
* @param isCall true for call
* @param rebate The rebate amount.
* @return The price.
*/
public double outBarrier(
final double spot,
final double barrierLevel,
final double strike,
final double expiry,
final double rate,
final double carry,
final double vol,
final boolean isCall,
final double rebate) {
final Function1D<Double, Double> intCon = ICP.getEuropeanPayoff(strike, isCall);
final ConvectionDiffusionPDE1DStandardCoefficients pde =
PDE.getBlackScholes(rate, rate - carry, vol);
final boolean isUp = barrierLevel > spot;
final double adj = 0.0; // _lambda == 0 ? ZETA * vol * Math.sqrt(expiry / (_nTNodes - 1)) : 0.0;
// System.out.println("adjustment: " + adj);
double sMin;
double sMax;
BoundaryCondition lower;
BoundaryCondition upper;
if (isUp) {
sMin = 0.0;
sMax =
barrierLevel
* Math.exp(-adj); // bring the barrier DOWN slightly to adjust for discrete monitoring
if (isCall) {
lower = new DirichletBoundaryCondition(0.0, sMin);
} else {
Function1D<Double, Double> lowerValue =
new Function1D<Double, Double>() {
@Override
public Double evaluate(Double tau) {
return Math.exp(-rate * tau) * strike;
}
};
lower = new DirichletBoundaryCondition(lowerValue, sMin);
}
upper = new DirichletBoundaryCondition(rebate, sMax);
} else {
sMin =
barrierLevel
* Math.exp(adj); // bring the barrier UP slightly to adjust for discrete monitoring
sMax = spot * Math.exp(_z * Math.sqrt(expiry));
lower = new DirichletBoundaryCondition(rebate, sMin);
if (isCall) {
Function1D<Double, Double> upperValue =
new Function1D<Double, Double>() {
@Override
public Double evaluate(Double tau) {
return Math.exp(-rate * tau) * (spot * Math.exp(carry * tau) - strike);
}
};
upper = new DirichletBoundaryCondition(upperValue, sMax);
} else {
upper = new DirichletBoundaryCondition(0.0, sMax);
}
}
final MeshingFunction tMesh = new ExponentialMeshing(0, expiry, _nTNodes, _lambda);
final MeshingFunction xMesh = new HyperbolicMeshing(sMin, sMax, spot, _nXNodes, _bunching);
final PDEGrid1D grid = new PDEGrid1D(tMesh, xMesh);
PDE1DDataBundle<ConvectionDiffusionPDE1DCoefficients> pdeData =
new PDE1DDataBundle<ConvectionDiffusionPDE1DCoefficients>(pde, intCon, lower, upper, grid);
PDEResults1D res = SOLVER.solve(pdeData);
// for now just do linear interpolation on price. TODO replace this with something more robust
final double[] xNodes = grid.getSpaceNodes();
final int index = SurfaceArrayUtils.getLowerBoundIndex(xNodes, spot);
final double w = (xNodes[index + 1] - spot) / (xNodes[index + 1] - xNodes[index]);
return w * res.getFunctionValue(index) + (1 - w) * res.getFunctionValue(index + 1);
}