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R1106/solutions/chapter-07/ch-07-ex-03-solution.cpp
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ch-07-ex-03-solution.cpp
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/*
* chapter-07-exercise-03.cpp
*
* ODE solver
*
* Created on: Oct 25, 2012
* Author: Radu Popescu <radu.popescu@epfl.ch>
*/
#include <cstdlib>
#include <iostream>
#include <fstream>
#include "AbstractOdeSolver.hpp"
#include "ForwardEulerSolver.hpp"
#include "RungeKuttaSolver.hpp"
double fRhs(double y, double t)
{
return 1 + t;
}
int main(int argc, char* argv[])
{
if (argc != 3) {
std::cout << "Missing paremeter. Please run as:\n"
<< " ./ch-07-ex-03-solution <stepsize_euler> <stepsize_rk>\n"
<< "Aborting.\n";
return 1;
}
double initialTime = 0.0;
double finalTime = 1.0;
double initialValue = 2.0;
AbstractOdeSolver* pSolver = 0;
// Solving with forward-Euler
double stepSizeEuler = std::atof(argv[1]);
pSolver = new ForwardEulerSolver;
pSolver->SetInitialValue(initialValue);
pSolver->SetTimeInterval(initialTime, finalTime);
pSolver->SetStepSize(stepSizeEuler);
pSolver->SetRightHandSide(fRhs);
std::ofstream eulerSolutionFile("solution_euler.dat");
if (eulerSolutionFile.is_open()) {
pSolver->SolveEquation(eulerSolutionFile);
eulerSolutionFile.close();
} else {
std::cout << "Couldn't open solution_euler.dat. Aborting."
<< std::endl;
return 1;
}
double stepSizeRK = std::atof(argv[2]);
pSolver = new RungeKuttaSolver;
pSolver->SetInitialValue(initialValue);
pSolver->SetTimeInterval(initialTime, finalTime);
pSolver->SetStepSize(stepSizeRK);
pSolver->SetRightHandSide(fRhs);
std::ofstream RKSolutionFile("solution_rk.dat");
if (RKSolutionFile.is_open()) {
pSolver->SolveEquation(RKSolutionFile);
RKSolutionFile.close();
} else {
std::cout << "Couldn't open solution_rk.dat. Aborting."
<< std::endl;
return 1;
}
return 0;
}
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