//ODE_MersonVariationalStep.cpp	
//變步長積分默森法

#include <iostream>							//輸入輸出流頭文件
#include "OrdinaryDifferentialEguation.h"	//求解常微分方程(組)頭文件
using namespace std;						//名字空間

void main(void)
{	
	double y[2] = {0.0, 1.0}, t(0.0), h(0.1), eps(FLOATERROR);
	valarray<double> vy(y, 2);
	matrix<double> vz(2,11);
	
  	cout.setf(ios::fixed);	//輸出數據為定點法
	cout.precision(6);		//精度6位

	ODE_MersonVariationalStep(t,h,2,vy,eps,11,vz);

	for(int i=0; i<11; i++)
	{
		double x = h * i;
		cout << "t = " << x << endl;
		cout << "    y(0) = " << vz(0, i) << "\t   y(1) = " << vz(1, i) << endl;
    }
}

//計算微分方程組中各方程右端函數值
template <class _Ty>
void FunctionValueMVS(_Ty t, valarray<_Ty>& y, valarray<_Ty>& d)
{
	_Ty q;

	int n = y.size();	//微分方程組中方程的個數，也是未知函數的個數

    q = 60.0 * (0.06 + t* (t - 0.6));
    d[0] = q * y[1];
	d[1] = -q * y[0];
}