原创 高斯10点积分法

/********************************************************************
* 用高斯10点法计算函数f(x)从a到b的积分值
* 输入: f--函数f(x)的指针
*       a--积分下限
*       b--积分上限
* 输出: 返回值为f(x)从a点到b点的积分值
*******************************************************************/
double gauss_legendre(double(*f)(double),double a,double b)
{
const int n="10";
const double z[10]={-0.9739065285,-0.8650633677,-0.6794095683,
-0.4333953941,-0.1488743390,0.1488743390,
0.4333953941,0.6794095683,0.8650633677,
0.9739065285};
const double w[10]={0.0666713443,0.1494513492,0.2190863625,
0.2692667193,0.2955242247,0.2955242247,
0.2692667193,0.2190863625,0.1494513492,
0.0666713443};
double y,gg;
int i;
gg=0.0;
for(i=0;i<n;i++)
{
y=(z*(b-a)+a+b)/2.0;
gg+=w*(*f)((double)y);
}
return((double)((gg*(b-a)/2.0)));
}