QuantLib
A free/open-source library for quantitative finance
Reference manual - version 1.20
Classes | List of all members
StochasticProcess1D Class Referenceabstract

1-dimensional stochastic process More...

#include <ql/stochasticprocess.hpp>

+ Inheritance diagram for StochasticProcess1D:

Classes

class  discretization
 discretization of a 1-D stochastic process More...
 

1-D stochastic process interface

ext::shared_ptr< discretizationdiscretization_
 
virtual Real x0 () const =0
 returns the initial value of the state variable
 
virtual Real drift (Time t, Real x) const =0
 returns the drift part of the equation, i.e. \( \mu(t, x_t) \)
 
virtual Real diffusion (Time t, Real x) const =0
 returns the diffusion part of the equation, i.e. \( \sigma(t, x_t) \)
 
virtual Real expectation (Time t0, Real x0, Time dt) const
 
virtual Real stdDeviation (Time t0, Real x0, Time dt) const
 
virtual Real variance (Time t0, Real x0, Time dt) const
 
virtual Real evolve (Time t0, Real x0, Time dt, Real dw) const
 
virtual Real apply (Real x0, Real dx) const
 
 StochasticProcess1D ()
 
 StochasticProcess1D (const ext::shared_ptr< discretization > &)
 

Additional Inherited Members

- Public Types inherited from Observer
typedef boost::unordered_set< ext::shared_ptr< Observable > > set_type
 
typedef set_type::iterator iterator
 
- Public Member Functions inherited from StochasticProcess
virtual Size factors () const
 returns the number of independent factors of the process
 
virtual Time time (const Date &) const
 
void update ()
 
- Public Member Functions inherited from Observer
 Observer (const Observer &)
 
Observeroperator= (const Observer &)
 
std::pair< iterator, bool > registerWith (const ext::shared_ptr< Observable > &)
 
void registerWithObservables (const ext::shared_ptr< Observer > &)
 
Size unregisterWith (const ext::shared_ptr< Observable > &)
 
void unregisterWithAll ()
 
virtual void deepUpdate ()
 
- Public Member Functions inherited from Observable
 Observable (const Observable &)
 
Observableoperator= (const Observable &)
 
void notifyObservers ()
 
- Protected Member Functions inherited from StochasticProcess
 StochasticProcess ()
 
 StochasticProcess (const ext::shared_ptr< discretization > &)
 
- Protected Attributes inherited from StochasticProcess
ext::shared_ptr< discretizationdiscretization_
 

Detailed Description

1-dimensional stochastic process

This class describes a stochastic process governed by

\[ dx_t = \mu(t, x_t)dt + \sigma(t, x_t)dW_t. \]

Member Function Documentation

◆ expectation()

virtual Real expectation ( Time  t0,
Real  x0,
Time  dt 
) const
virtual

returns the expectation \( E(x_{t_0 + \Delta t} | x_{t_0} = x_0) \) of the process after a time interval \( \Delta t \) according to the given discretization. This method can be overridden in derived classes which want to hard-code a particular discretization.

Reimplemented in OrnsteinUhlenbeckProcess, MfStateProcess, HullWhiteForwardProcess, HullWhiteProcess, GsrProcess, CoxIngersollRossProcess, GeneralizedBlackScholesProcess, GeneralizedOrnsteinUhlenbeckProcess, and ExtendedOrnsteinUhlenbeckProcess.

◆ stdDeviation()

virtual Real stdDeviation ( Time  t0,
Real  x0,
Time  dt 
) const
virtual

returns the standard deviation \( S(x_{t_0 + \Delta t} | x_{t_0} = x_0) \) of the process after a time interval \( \Delta t \) according to the given discretization. This method can be overridden in derived classes which want to hard-code a particular discretization.

Reimplemented in OrnsteinUhlenbeckProcess, MfStateProcess, HullWhiteForwardProcess, HullWhiteProcess, GsrProcess, CoxIngersollRossProcess, GeneralizedBlackScholesProcess, GeneralizedOrnsteinUhlenbeckProcess, GemanRoncoroniProcess, and ExtendedOrnsteinUhlenbeckProcess.

◆ variance()

virtual Real variance ( Time  t0,
Real  x0,
Time  dt 
) const
virtual

returns the variance \( V(x_{t_0 + \Delta t} | x_{t_0} = x_0) \) of the process after a time interval \( \Delta t \) according to the given discretization. This method can be overridden in derived classes which want to hard-code a particular discretization.

Reimplemented in GsrProcess, OrnsteinUhlenbeckProcess, MfStateProcess, HullWhiteForwardProcess, HullWhiteProcess, CoxIngersollRossProcess, GeneralizedBlackScholesProcess, GeneralizedOrnsteinUhlenbeckProcess, and ExtendedOrnsteinUhlenbeckProcess.

◆ evolve()

virtual Real evolve ( Time  t0,
Real  x0,
Time  dt,
Real  dw 
) const
virtual

returns the asset value after a time interval \( \Delta t \) according to the given discretization. By default, it returns

\[ E(x_0,t_0,\Delta t) + S(x_0,t_0,\Delta t) \cdot \Delta w \]

where \( E \) is the expectation and \( S \) the standard deviation.

Reimplemented in GeneralizedBlackScholesProcess, GemanRoncoroniProcess, and ExtendedBlackScholesMertonProcess.

◆ apply()

virtual Real apply ( Real  x0,
Real  dx 
) const
virtual

applies a change to the asset value. By default, it returns \( x + \Delta x \).

Reimplemented in Merton76Process, and GeneralizedBlackScholesProcess.