Function cross

dscribe/ext/geometry.cpp:21–23

using namespace std;

inline vector<double> cross(const vector<double>& a, const vector<double>& b) {
    return {a[1]*b[2]-a[2]*b[1], a[2]*b[0]-a[0]*b[2], a[0]*b[1]-a[1]*b[0]};
}

inline double dot(const vector<double>& a, const vector<double>& b) {
    return a[0]*b[0] + a[1]*b[1] + a[2]*b[2];