erfcc.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 15 行

double erfcc(double x)
{
	double z,t,ddd,aaa,bbb,ccc,temp;
    z = fabs(x);
    t = 1.0 / (1.0 + 0.5 * z);
    ddd = -0.82215223 + t * 0.17087277;
    aaa = t * (-1.13520398 + t * (1.48851587 + t * ddd));
    bbb = t * (-0.18628806 + t * (0.27886807 + aaa));
    ccc = t * (0.37409196 + t * (0.09678418 + bbb));
    temp= t * exp(-z * z - 1.26551223 + t * (1.00002368 + ccc));
    if (x < 0.0) 
		temp= 2.0 - temp;
	return temp;
}