qromo.cpp

来自「提供了6种数值积分方法的c++代码实现： 1 梯形求积法(TRAPZD->」· C++ 代码 · 共 40 行

void qromo(double a, double b, double& ss, char pick[])
{
    double dss,eps = 0.00003;
    int jmaxp,jmax = 14;
    jmaxp = jmax + 1;
    int k = 7;
    double s[15], h[15];
    h[1] = 1.0;
    for (int j = 1; j<=jmax; j++)
	{
        if (strcmp(pick,"midpnt")==0)
		{
			midpnt(a, b, s[j], j);
		}
        if (strcmp(pick,"midinf")==0)
		{
			midinf(a, b, s[j], j);
		}
        if (strcmp(pick,"midsql")==0)
		{
			midsql(a, b, s[j], j);
		}
        if (strcmp(pick,"midsqu")==0)
		{
			midsqu(a, b, s[j], j);
		}
        if (j > k)
		{
            polint(h, s, k, 0.0, ss, dss);
            if (fabs(dss) < eps * fabs(ss))
			{
				return;
			}
        }
        s[j + 1] = s[j];
        h[j + 1] = h[j] / 9.0;
    }
    cout<< "too many steps."<<endl;
}