G2TwoFactorModel





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Creates a two factor additive ShortRate Model object to be used within the interest rate Engines.

Defined as : dr_t = varphi(t) + x_t + y_t, where dx_t = -a*x_t*dt + sigma*dW^1_t, x_0 = 0, dy_t = -b*y_t*dt + sigma*dW^2_t, y_0 = 0 and dW^1_t*dW^2_t = rho*dt. This function can be calibrated by executing one of the calibration functions (functions with a naming convention of Calibrate*() ) within the CapeTools IR Calibration or CapeTools LMM Calibration category of functions.

Not all calibration functions can be used with each model.

The calibration parameters will be returned within an array in which you can you construct a new G2TwoFactorModel from.

You can create Pricing Engines from this G2TwoFactorModel model by executing one of the following functions : G2SwaptionEngine(), TreeSwaptionEngine(), AnalyticCapFloorEngine() or TreeCapFloorEngine(). In these latter functions, the string 'key' returned from this G2TwoFactorModel function acts as input to these Engine functions.



This function creates an object and returns a string-key value to represent this created object.
The TAG value of the string-key returned (second part of the key) is : "G2MOD"



Note: Within Excel, the function is named - CT.MOD.G2TwoFactorModel




High level graphic of G2TwoFactorModel() function with parameters. Blue square node is the actual function with the parameters ordered.



Parameter Description


  1. Key parameter

    Key value to use as a handle for the created object
  2. Reload parameter

    When creating this object for the first time, set this parameter to a positive value. Within Excel, when re-computing a worksheet where you do not wish to recreate the object, set this parameter to zero (0).
  3. alpha parameter

    alpha parameter, default value is 0.1.
  4. sigma parameter

    standard deviation of the short rate, default value is 0.01.
  5. beta parameter

    beta parameter, default value is 0.1.
  6. eta parameter

    eta parameter, default value is 0.01.
  7. rho parameter

    rho parameter, default value is -0.75.
  8. YCKey parameter

    Key to an already constructed yieldcurve object.


Extended information

Function Syntax

VB Syntax


String CTModels.G2TwoFactorModel( _
String Key, _
Long Reload, _
Double alpha, _
Double sigma, _
Double beta, _
Double eta, _
Double rho, _
String YCKey)


Excel Spreadsheet Syntax


=CT.MOD.G2TwoFactorModel(
Excel String Cell Key,
Excel Numeric Cell Reload,
Excel Numeric Cell alpha,
Excel Numeric Cell sigma,
Excel Numeric Cell beta,
Excel Numeric Cell eta,
Excel Numeric Cell rho,
Excel String Cell YCKey)


C++ Syntax


static std::string G2TwoFactorModel(
std::string Key,
long Reload,
double alpha,
double sigma,
double beta,
double eta,
double rho,
std::string YCKey);


DotNET Syntax


System.String CTModelsSA.G2TwoFactorModel(
System.String Key,
System.Int32 Reload,
System.Double alpha,
System.Double sigma,
System.Double beta,
System.Double eta,
System.Double rho,
System.String YCKey);

Parameter data types

ArgNameArgTypeIsKey
KeyStringFALSE
ReloadLongFALSE
alphaDoubleFALSE
sigmaDoubleFALSE
betaDoubleFALSE
etaDoubleFALSE
rhoDoubleFALSE
YCKeyStringTRUE


Example Inputs

The first column represents the name of the parameters. The second column specifies whether the parameters are optional or not. Finally the last column provides some sample input data.
Function call input string-keys are always in the format : "NAME.EXTTAG.TICKER" The "EXTTAG.TICKER" part is determined from the output of other, capetools, object creation functions.


ArgNameIsOptional (Excel only)Example
KeyFALSEMyG2TwoFactorModel
ReloadFALSE1
alphaTRUE0.527817475
sigmaTRUE0.024489696
betaTRUE0.11883967
etaTRUE0.018316489
rhoTRUE-0.893319042
YCKeyFALSEYCKeyNAME.EXTTAG.TICKER (from a function call)


Example function usage


The C# example below contains all the sub-function calls leading up to this function call. As a result, the example can contain a lot of code.

The VB.NET, J#, C++.NET, Java, Excel VBA, Visual Basic 6 (via COM) and C++ examples below contain function code stubs for the calls leading up to this function call. However, the function call for this function is displayed.
You can easily reproduce the stub functions code from the C# example.


If you are accessing this functrion via the MiniXL libraries, this function is present within the CT.QL.Models20 MiniXL Excel Addin.

Within our Excel Example Addin Generator, we have used the following QuantTools sub-functions in order to prepare the arguments needed to call the G2TwoFactorModel() function. If you are executing this function via the MiniXL libraries, the module addin name, (in brackets, to the right of the sub-functions listed below), indicates the MiniXL library in which the sub-function is held. You will need to load this library into your Excel session (along with any other libraries that the sub-function call within the addin requires (ie - CT.QT.Utils20 addin in almost all cases) in order for the example to compute successfully.

These are the financial QuantTools sub-function calls that are used within the examples :





The objects generated by these sub-functions are inter-connected in the following way :




The following four examples demostrate calling this function within a Microsoft .NET environment

The following four examples demostrate calling this function within a non .NET environment

The following is a sample output from executing the G2TwoFactorModel() function call


MyG2TwoFactorModel_2.G2MOD.0

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