Chaste  Release::3.4
HeunIvpOdeSolver.cpp
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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
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)
#define CHASTE_CLASS_EXPORT(T)