Chaste Commit::baa90ac2819b962188b7562f2326be23c47859a7
HeunIvpOdeSolver.cpp
1/*
2
3Copyright (c) 2005-2024, University of Oxford.
4All rights reserved.
5
6University of Oxford means the Chancellor, Masters and Scholars of the
7University of Oxford, having an administrative office at Wellington
8Square, Oxford OX1 2JD, UK.
9
10This file is part of Chaste.
11
12Redistribution and use in source and binary forms, with or without
13modification, are permitted provided that the following conditions are met:
14 * Redistributions of source code must retain the above copyright notice,
15 this list of conditions and the following disclaimer.
16 * Redistributions in binary form must reproduce the above copyright notice,
17 this list of conditions and the following disclaimer in the documentation
18 and/or other materials provided with the distribution.
19 * Neither the name of the University of Oxford nor the names of its
20 contributors may be used to endorse or promote products derived from this
21 software without specific prior written permission.
22
23THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
24AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
27LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
29GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33
34*/
35
36//Heun's Method
37//Megan Lewis, University of Saskatchewan
38//January 2009
39#include "HeunIvpOdeSolver.hpp"
40
42 double timeStep,
43 double time,
44 std::vector<double>& rCurrentYValues,
45 std::vector<double>& rNextYValues)
46{
47 /*
48 * Apply Heun 2nd order method for each time step in AbstractOneStepIvpSolver.
49 * Calculates a vector containing the next Y value from the current one for each
50 * equation in the system.
51 */
52
53 const unsigned num_equations = pAbstractOdeSystem->GetNumberOfStateVariables();
54
55 std::vector<double> k1(num_equations);
56 std::vector<double> k2(num_equations);
57 std::vector<double>& dy = rNextYValues; // re-use memory
58
59 // Work out k1
60 pAbstractOdeSystem->EvaluateYDerivatives(time, rCurrentYValues, k1);
61
62 // Add current y values to k1 values
63 for (unsigned i=0; i<num_equations; i++)
64 {
65 dy[i] = timeStep*k1[i] + rCurrentYValues[i];
66 }
67 //Work out k2
68 pAbstractOdeSystem->EvaluateYDerivatives(time+timeStep, dy, k2);
69
70 // New solution
71 for (unsigned i=0; i<num_equations; i++)
72 {
73 rNextYValues[i] = rCurrentYValues[i] + timeStep*0.5*(k1[i] + k2[i]);
74 }
75}
76
77
78// Serialization for Boost >= 1.36
#define CHASTE_CLASS_EXPORT(T)
virtual void EvaluateYDerivatives(double time, const std::vector< double > &rY, std::vector< double > &rDY)=0
void CalculateNextYValue(AbstractOdeSystem *pAbstractOdeSystem, double timeStep, double time, std::vector< double > &rCurrentYValues, std::vector< double > &rNextYValues)