public void Go()
{
_initialGuess = new DenseVector(_p.NumberOfExpiries * _p.NumberOfTenors);
double initialGuess = _p.AverageSwaptionImpliedVolatility;
if (initialGuess == 0)
{
initialGuess = _p.AverageCapletImpliedVolatility;
}
if (initialGuess == 0)
{
throw new Exception("The selected time range does not include any calibration targets.");
}
if (_objective.ExpForm)
{
for (var i = 0; i < _initialGuess.Count; i++)
{
_initialGuess[i] = Math.Log(initialGuess) / 20;
}
}
else
{
for (var i = 0; i < _initialGuess.Count; i++)
{
_initialGuess[i] = initialGuess;
}
}
var sw = new StopWatch();
_objective.StartOtherThreads();
var solution = BfgsSolver.Solve(_initialGuess, _f, _g);
_objective.Finished = true;
sw.Stop();
TimeSpan ts = sw.GetElapsedTime();
Pedersen.Write($" Value x: {solution[0]}\n", "cal");
_objective.OutputResult(solution);
Pedersen.Write($" Process Time: {ts.Hours:d2}:{ts.Minutes:d2}:{ts.Seconds:d2}:{ts.Milliseconds:d3}\n", "cal");
}
/// <summary>
/// Main calibration method.
/// </summary>
/// <param name="timeGrid">Time discretisation</param>
/// <param name="discount">Quarterly discount factors</param>
/// <param name="shift">Quarterly shift values</param>
/// <param name="correlation">Correlation matrix, corresponding the tenor time discretisation</param>
/// <param name="targets">Caplet and swaption implied vols</param>
/// <param name="parameters">Calibration settings</param>
/// <param name="factors">Factors used</param>
/// <param name="useCascade">Whether to apply cascade algorithm post-calibration</param>
/// <param name="output"></param>
/// <returns></returns>
public static InterestRateVolatilities Calibrate(PedersenTimeGrid timeGrid, QuarterlyDiscounts discount,
QuarterlyShifts shift, DenseMatrix correlation, CalibrationTargets targets,
CalibrationSettings parameters, int factors, bool useCascade, ref string output)
{
#region Initialisations
targets.AdjustImpliedVolsForShift(discount, shift);
var swaptionWeights = new SwaptionWeights(timeGrid.MaxExpiry, timeGrid.MaxTenor);
swaptionWeights.Populate(discount, shift);
var volatilities = new InterestRateVolatilities(timeGrid, factors, swaptionWeights, correlation);
var objective = new CalibrationObjective(targets, timeGrid, volatilities, parameters);
Func <Vector <double>, double> f = objective.ObjFun;
Func <Vector <double>, Vector <double> > g = objective.ObjGrad;
var initialGuess = new DenseVector(timeGrid.ExpiryCount * timeGrid.TenorCount);
double guessValue = targets.AverageImpliedVol();
if (guessValue == 0)
{
throw new Exception("The selected time range does not include any calibration targets.");
}
if (parameters.ExponentialForm)
{
for (var i = 0; i < initialGuess.Count; i++)
{
initialGuess[i] = Math.Log(guessValue) / 20;
}
}
else
{
for (var i = 0; i < initialGuess.Count; i++)
{
initialGuess[i] = guessValue;
}
}
Trace.WriteLine(String.Format("Calibration Starting..."));
objective.StartOtherThreads();
var solution = BfgsSolver.Solve(initialGuess, f, g);
objective.Finished = true;
Trace.WriteLine($"Value at extremum: {solution}");
objective.PopulateVol(solution);
objective.AverageAbsVol();
#endregion
#region Cascade
if (useCascade)
{
Trace.WriteLine(String.Format("Applying Cascade Algorithm..."));
var cascade = new CascadeAlgorithm(volatilities, timeGrid, swaptionWeights, targets, parameters.CascadeParam, factors);
cascade.ApplyCascade();
}
#endregion
#region Output
output = objective.AverageAbsVol();
return(objective.ReturnVol(solution));
#endregion
}
private static void CheckRosenbrock(double a, double b, double expectedMin)
{
var x = BfgsSolver.Solve(new DenseVector(new[] { a, b }), RosenbrockFunction.Value, RosenbrockFunction.Gradient);
Numerics.Precision.AlmostEqual(expectedMin, RosenbrockFunction.Value(x), Precision);
}
