double FlowField::CalcAngularError(FlowField &t){
std::pair<int, int> size = Size();
double amount = 0;
double tmp1 = 0;
double tmp2 = 0;
double sum_l2 = 0;
double sum_ang = 0;
// make sure both flow field have same size
if (size != t.Size()){
std::cout << "Dimensions in CalcAngularError dont match" << std::endl;
std::exit(1);
}
for (int i = 0; i < size.first; i++) {
for (int j = 0; j < size.second; j++){
// test if reference flow vector exists
if (t.u[i][j] != 100.0 || t.v[i][j] != 100.0){
amount++;
tmp1 = t.u[i][j] - u[i][j];
tmp2 = t.v[i][j] - v[i][j];
sum_l2 += sqrt(tmp1*tmp1 + tmp2*tmp2);
tmp1 = (t.u[i][j] * u[i][j] + t.v[i][j] * v[i][j] + 1.0)
/ sqrt( (t.u[i][j] * t.u[i][j] + t.v[i][j] * t.v[i][j] + 1.0)
* (u[i][j] * u[i][j] + v[i][j] * v[i][j] + 1.0) );
if (tmp1 > 1.0) tmp1 = 1.0;
if (tmp1 < - 1.0) tmp1 = - 1.0;
sum_ang += acos(tmp1) * 180.0/M_PI;
}
}
}
return sum_ang / amount;
}
