FitzHughNagumo1961OdeSystem.cpp

00001 /*
00002 
00003 Copyright (C) University of Oxford, 2005-2010
00004 
00005 University of Oxford means the Chancellor, Masters and Scholars of the
00006 University of Oxford, having an administrative office at Wellington
00007 Square, Oxford OX1 2JD, UK.
00008 
00009 This file is part of Chaste.
00010 
00011 Chaste is free software: you can redistribute it and/or modify it
00012 under the terms of the GNU Lesser General Public License as published
00013 by the Free Software Foundation, either version 2.1 of the License, or
00014 (at your option) any later version.
00015 
00016 Chaste is distributed in the hope that it will be useful, but WITHOUT
00017 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00018 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
00019 License for more details. The offer of Chaste under the terms of the
00020 License is subject to the License being interpreted in accordance with
00021 English Law and subject to any action against the University of Oxford
00022 being under the jurisdiction of the English Courts.
00023 
00024 You should have received a copy of the GNU Lesser General Public License
00025 along with Chaste. If not, see <http://www.gnu.org/licenses/>.
00026 
00027 */
00028 #include "FitzHughNagumo1961OdeSystem.hpp"
00029 #include "OdeSystemInformation.hpp"
00030 #include <cmath>
00031 
00032 //
00033 // Model-scope constant parameters
00034 //
00035 const double FitzHughNagumo1961OdeSystem::mAlpha = -0.08;
00036 const double FitzHughNagumo1961OdeSystem::mGamma = 3.00;
00037 const double FitzHughNagumo1961OdeSystem::mEpsilon = 0.005;
00038 
00039 
00040 FitzHughNagumo1961OdeSystem::FitzHughNagumo1961OdeSystem(
00041         boost::shared_ptr<AbstractIvpOdeSolver> pOdeSolver,
00042         boost::shared_ptr<AbstractStimulusFunction> pIntracellularStimulus)
00043     : AbstractCardiacCell(pOdeSolver, 2, 0, pIntracellularStimulus)
00044 {
00045     mpSystemInfo = OdeSystemInformation<FitzHughNagumo1961OdeSystem>::Instance();
00046 
00047     Init();
00048 }
00049 
00050 FitzHughNagumo1961OdeSystem::~FitzHughNagumo1961OdeSystem(void)
00051 {
00052 }
00053 
00054 void FitzHughNagumo1961OdeSystem::EvaluateYDerivatives(double time, const std::vector<double> &rY, std::vector<double>& rDY)
00055 {
00056     double membrane_V = rY[0]; // v
00057     double recovery_variable = rY[1]; // w
00058 
00059     double i_stim = GetStimulus(time);
00060 
00061     // dV/dt
00062     double membrane_V_prime = membrane_V*(membrane_V-mAlpha)*(1-membrane_V)-recovery_variable+i_stim;
00063     // do not update voltage if the mSetVoltageDerivativeToZero flag has been set
00064     if (mSetVoltageDerivativeToZero)
00065     {
00066         membrane_V_prime = 0;
00067     }
00068 
00069     // dw/dt
00070     double recovery_variable_prime = mEpsilon*(membrane_V-mGamma*recovery_variable);
00071 
00072     rDY[0] = membrane_V_prime;
00073     rDY[1] = recovery_variable_prime;
00074 }
00075 
00076 double FitzHughNagumo1961OdeSystem::GetIIonic()
00077 {
00078     double membrane_V = mStateVariables[mVoltageIndex];
00079     double recovery_variable = mStateVariables[1];
00080     double fake_ionic_current = membrane_V*(membrane_V-mAlpha)*(1-membrane_V)-recovery_variable;
00081     return fake_ionic_current;
00082 }
00083 
00084 
00085 
00086 
00087 template<>
00088 void OdeSystemInformation<FitzHughNagumo1961OdeSystem>::Initialise(void)
00089 {
00090     /*
00091      * State variables
00092      */
00093     this->mVariableNames.push_back("V");
00094     this->mVariableUnits.push_back("mV");
00095     this->mInitialConditions.push_back(0.0);
00096 
00097     this->mVariableNames.push_back("w");
00098     this->mVariableUnits.push_back("");
00099     this->mInitialConditions.push_back(0.0);
00100 
00101     this->mInitialised = true;
00102 }

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