/// <summary>
/// The main constructor for the Coordinator.
/// </summary>
/// <param name="numeraireSimulator">A special simulator that also includes the numeraire. There is only one of these.</param>
/// <param name="availableSimulators">Optionally any extra simulators independent of the first. Can be an empty list.</param>
/// <param name="numberOfPaths"></param>
public Coordinator(NumeraireSimulator numeraireSimulator, List <Simulator> availableSimulators,
int numberOfPaths)
{
_numeraireSimulator = numeraireSimulator;
_availableSimulators = availableSimulators;
_numberOfPaths = numberOfPaths;
}
private static MarketObservable GetCcyPair(NumeraireSimulator numeraireSimulator, Currency ccy)
{
// TODO: Currency pair should be passed in somehow rather than constructed here so that there is no risk of names not coinciding.
MarketObservable index = new CurrencyPair($"{ccy}{numeraireSimulator.GetNumeraireCurrency()}",
ccy, numeraireSimulator.GetNumeraireCurrency());
return(index);
}
/// <summary>
/// The main constructor for the Coordinator.
/// </summary>
/// <param name="numeraire">A special simulator that also includes the numeraire. There is only one of these.</param>
/// <param name="simulators">Optionally any extra simulators independent of the first. Can be an empty list.</param>
public Coordinator(NumeraireSimulator numeraire, List <Simulator> simulators, int N)
{
this.numeraire = numeraire;
this.simulators = simulators;
this.simulators.Insert(0, numeraire);
this.N = N;
valueCurrency = numeraire.GetNumeraireCurrency();
}
/// <summary>
/// Copies the simulators into local variables so that they can be safely used on a thread
/// without changing the originals.
/// </summary>
/// <param name="localNumeraire">The local numeraire. The reference to this object is changed in the call.</param>
/// <param name="localSimulators">The local simulators.</param>
/// <exception cref="System.NotImplementedException"></exception>
private void CopySimulators(out NumeraireSimulator localNumeraire, out List <Simulator> localSimulators)
{
localSimulators = new List <Simulator>();
foreach (Simulator simulator in simulators)
{
localSimulators.Add(simulator.Clone());
}
localNumeraire = (NumeraireSimulator)localSimulators[0];
}
/// <summary>
/// Creates a lookup so that the coordinator knows which simulator provides each required index.
/// </summary>
/// <exception cref="System.ArgumentException">
/// Cannot use 'ANY' as the valuation currency when the portfolio includes cashflows in multiple currencies.
/// </exception>
/// <exception cref="System.IndexOutOfRangeException">
/// Required index: " + index.ToString() + " is not provided by any of the simulators.
/// or
/// Required currency pair: " + index.ToString() + " is not provided by any of the simulators
/// </exception>
private static Dictionary <MarketObservable, Simulator> AssociateFactorsWithSimulators(
IEnumerable <IProduct> portfolio,
NumeraireSimulator numeraireSimulator,
List <Simulator> availableSimulators)
{
// Find which simulator will provide each of the potentially required MarketObservables.
var mappedSimulators = new Dictionary <MarketObservable, Simulator>();
var indices = new HashSet <MarketObservable>();
foreach (var product in portfolio)
{
foreach (var index in product.GetRequiredIndices())
{
indices.Add(index);
}
foreach (var ccy in product.GetCashflowCurrencies().Where(c => c != numeraireSimulator.GetNumeraireCurrency()))
{
indices.Add(GetCcyPair(numeraireSimulator, ccy));
}
}
foreach (var index in indices)
{
if (mappedSimulators.ContainsKey(index))
{
continue;
}
var found = false;
foreach (var sim in availableSimulators)
{
if (!sim.ProvidesIndex(index))
{
continue;
}
if (!found)
{
mappedSimulators[index] = sim;
found = true;
}
else
{
throw new ArgumentException(index + " is provided by more than one simulator.");
}
}
if (found)
{
continue;
}
throw new IndexOutOfRangeException("Required index: " + index +
" is not provided by any of the simulators.");
}
return(mappedSimulators);
}
/// <summary>
/// Initializes the simulators by telling them at which dates they will need to provide which market indices.
/// </summary>
/// <param name="valueDate"></param>
/// <param name="portfolio"></param>
/// <param name="fwdDates">Extra dates over and above the contract dates where the simulators will need to
/// provide their indices. This is likely to be forward values required in EPE and PFE profiles.</param>
/// <param name="numeraireSimulator"></param>
/// <param name="mappedSimulators"></param>
/// <param name="availableSimulators"></param>
private static void PrepareSimulators(Date valueDate, List <IProduct> portfolio, List <Date> fwdDates,
NumeraireSimulator numeraireSimulator, Dictionary <MarketObservable, Simulator> mappedSimulators,
List <Simulator> availableSimulators)
{
// Reset all the simulators
foreach (var simulator in availableSimulators)
{
simulator.Reset();
}
// Set up the simulators for the times at which they will be queried
foreach (var product in portfolio)
{
product.SetValueDate(valueDate);
// Tell the simulators at what times indices will be required.
foreach (var index in product.GetRequiredIndices())
{
var requiredTimes = product.GetRequiredIndexDates(index);
mappedSimulators[index].SetRequiredDates(index, requiredTimes);
mappedSimulators[index].SetRequiredDates(index, fwdDates);
}
// Tell the numeraire simulator at what times it will be required.
// Tell the FX simulators at what times they will be required.
foreach (var ccy in product.GetCashflowCurrencies())
{
var requiredDates = product.GetCashflowDates(ccy);
numeraireSimulator.SetNumeraireDates(requiredDates);
numeraireSimulator.SetNumeraireDates(fwdDates);
if (ccy != numeraireSimulator.GetNumeraireCurrency())
{
var ccyPair = GetCcyPair(numeraireSimulator, ccy);
mappedSimulators[ccyPair].SetRequiredDates(ccyPair, requiredDates);
mappedSimulators[ccyPair].SetRequiredDates(ccyPair, fwdDates);
}
}
foreach (var simulator in availableSimulators)
{
simulator.Prepare(valueDate);
}
numeraireSimulator.Prepare(valueDate);
}
// Prepare all the simulators
foreach (var simulator in availableSimulators)
{
simulator.Prepare(valueDate);
}
}
/// <summary>
/// Performs the simulation chunk that updates
/// the cashflows per product and per path.
/// the
/// </summary>
/// <param name="portfolio"></param>
/// <param name="fwdValueDates">The dates at which the underlying factors will be saved for later regression.</param>
/// <param name="simulatedCFs">The cashflows converted to the value currency and deflated witht he numeaire. Updated
/// by this function.</param>
/// <param name="simulatedRegs">The valuesor the regressors by path and date.</param>
/// <param name="pathStart">The path start.</param>
/// <param name="pathEnd">The path end.</param>
private void PerformSimulationChunk(List <Product> portfolio, List <Date> fwdValueDates,
SimulatedCashflows simulatedCFs, SimulatedRegressors simulatedRegs, int pathStart, int pathEnd)
{
// clone the simulators and portfolio if this is running multi threaded
List <Product> localPortfolio;
NumeraireSimulator localNumeraire = null;
List <Simulator> localSimulators = null;
if (useThreads)
{
localPortfolio = portfolio.Clone();
CopySimulators(out localNumeraire, out localSimulators);
}
else
{
localPortfolio = portfolio;
localNumeraire = numeraire;
localSimulators = simulators;
}
for (int pathCounter = pathStart; pathCounter < pathEnd; pathCounter++)
{
double numeraireAtValue = localNumeraire.Numeraire(valueDate);
// Run the simulation
foreach (Simulator simulator in localSimulators)
{
simulator.RunSimulation(pathCounter);
}
// get the underlying factors
for (int fwdDateCounter = 0; fwdDateCounter < fwdValueDates.Count; fwdDateCounter++)
{
int independentCounter = 0;
foreach (Simulator simulator in localSimulators)
{
double[] underlyingFactors = simulator.GetUnderlyingFactors(fwdValueDates[fwdDateCounter]);
for (int thisIndependentCounter = 0; thisIndependentCounter < underlyingFactors.Length; thisIndependentCounter++)
{
simulatedRegs.Add(pathCounter, fwdDateCounter, independentCounter, underlyingFactors[thisIndependentCounter]);
independentCounter++;
}
}
}
// use the simulators that now contain a simulation to provide market observables to the
// products.
for (int productCounter = 0; productCounter < localPortfolio.Count; productCounter++)
{
Product product = localPortfolio[productCounter];
product.Reset();
foreach (MarketObservable index in product.GetRequiredIndices())
{
Simulator simulator = localSimulators[indexSources[index]];
List <Date> requiredDates = product.GetRequiredIndexDates(index);
double[] indices = simulator.GetIndices(index, requiredDates);
product.SetIndexValues(index, indices);
}
List <Cashflow> timesAndCFS = product.GetCFs();
foreach (Cashflow cf in timesAndCFS)
{
if (cf.currency.Equals(valueCurrency))
{
double cfValue = cf.amount * numeraireAtValue / localNumeraire.Numeraire(cf.date);
simulatedCFs.Add(productCounter, pathCounter, new Cashflow(cf.date, cfValue, cf.currency));
}
else
{
MarketObservable currencyPair = new CurrencyPair(cf.currency, localNumeraire.GetNumeraireCurrency());
Simulator simulator = localSimulators[indexSources[currencyPair]];
double fxRate = simulator.GetIndices(currencyPair, new List <Date> {
cf.date
})[0];
double cfValue = fxRate * cf.amount * numeraireAtValue / localNumeraire.Numeraire(cf.date);
simulatedCFs.Add(productCounter, pathCounter, new Cashflow(cf.date, cfValue, cf.currency));
}
}
}
}
}
