rkdumb.cpp

来自「提供了4种解常微分方程组的c++代码：定步长四阶龙格-库塔(Runge-Kutt」· C++ 代码 · 共 35 行

void rkdumb(double vstart[5], double nvar, double x1, double x2, double nstep, double xx[201], double y[11][201])
{
	int i,k;
    double v[11], dv[11],x,h;
    for( i = 1; i<=nvar; i++)
	{
        v[i] = vstart[i];
        y[i][ 1] = v[i];
    }
    xx[1] = x1;
    x = x1;
    h = (x2 - x1) / float(nstep);
    for( k = 1; k<=nstep; k++)
	{
        derivs(x, v, dv);
        rk4(v, dv, nvar, x, h, v);
        if( x + h == x)
		{
            cout<<" stepsize not signficant in rkdumb."<<endl;
            _c_exit();
        }
        x = x + h;
        xx[k + 1] = x;
        for( i = 1; i<=nvar; i++)
		{
            y[i][k + 1] = v[i];
        }
    }
    for(i=1; i<=10; i++)
	{
		v[i]=0.0;
		dv[i]=0.0;
	}
}