QuantLib: a free/open-source library for quantitative finance
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squarerootprocess.hpp
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1/* -*- mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2
3/*
4 Copyright (C) 2003 Ferdinando Ametrano
5 Copyright (C) 2001, 2002, 2003 Sadruddin Rejeb
6 Copyright (C) 2004, 2005 StatPro Italia srl
7
8 This file is part of QuantLib, a free-software/open-source library
9 for financial quantitative analysts and developers - http://quantlib.org/
10
11 QuantLib is free software: you can redistribute it and/or modify it
12 under the terms of the QuantLib license. You should have received a
13 copy of the license along with this program; if not, please email
14 <quantlib-dev@lists.sf.net>. The license is also available online at
15 <http://quantlib.org/license.shtml>.
16
17 This program is distributed in the hope that it will be useful, but WITHOUT
18 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
19 FOR A PARTICULAR PURPOSE. See the license for more details.
20*/
21
22/*! \file squarerootprocess.hpp
23 \brief square-root process
24*/
25
26#ifndef quantlib_square_root_process_hpp
27#define quantlib_square_root_process_hpp
28
31
32namespace QuantLib {
33
34 //! Square-root process class
35 /*! This class describes a square-root process governed by
36 \f[
37 dx = a (b - x_t) dt + \sigma \sqrt{x_t} dW_t.
38 \f]
39
40 \ingroup processes
41 */
43 public:
45 Real b, Real a, Volatility sigma, Real x0 = 0.0,
46 const ext::shared_ptr<discretization>& d =
47 ext::shared_ptr<discretization>(new EulerDiscretization));
48 //! \name StochasticProcess interface
49 //@{
50 Real x0() const override;
51 Real drift(Time t, Real x) const override;
52 Real diffusion(Time t, Real x) const override;
53 //@}
54
55 Real a() const { return speed_; }
56 Real b() const { return mean_; }
57 Real sigma() const { return volatility_; }
58 private:
61 };
62
63}
64
65
66#endif
Euler discretization for stochastic processes.
Square-root process class.
Real diffusion(Time t, Real x) const override
returns the diffusion part of the equation, i.e.
Real drift(Time t, Real x) const override
returns the drift part of the equation, i.e.
Real x0() const override
returns the initial value of the state variable
1-dimensional stochastic process
const DefaultType & t
Euler discretization for stochastic processes.
Date d
Real Time
continuous quantity with 1-year units
Definition: types.hpp:62
QL_REAL Real
real number
Definition: types.hpp:50
Real Volatility
volatility
Definition: types.hpp:78
Definition: any.hpp:35
stochastic processes