zbrak.cpp

来自「工程算法 这是一个很有用的工程数值算法集锦」· C++ 代码 · 共 24 行

void zbrak(double x1, double x2, int n, double xb1[], double xb2[], int& nb)
{
	int nbb,i;
	double dx,x,fc,fp;
    nbb = nb;
    nb = 0;
    x = x1;
    dx = (x2 - x1)/ n;
    fp = func(x);
    for (i = 1; i<=n; i++)
	{
        x = x + dx;
        fc = func(x);
        if ((fc * fp) < 0.0 )
		{
            nb = nb + 1;
            xb1[nb] = x - dx;
            xb2[nb] = x;
        }
        fp = fc;
        if (nbb == nb) exit(1);
    }
}