void eval_integrand(UserVector & output, std::vector<Scalar> & input) {
int dimension = (int)alpha.size();
Scalar total = 0.0;
Scalar point = 0.0;
for (int i=0; i<dimension; i++) {
point = 0.5*input[i]+0.5;
total += powl(alpha[i]*(point-beta[i]),(long double)2.0);
}
output.clear(); output.resize(1,std::exp(-total));
}
void eval_integrand(UserVector & output, std::vector<Scalar> & input) {
output.clear(); output.resize(1,std::exp(-input[0]*input[0])
+10.0*std::exp(-input[1]*input[1]));
}
void eval_integrand(UserVector & output, std::vector<Scalar> & input) {
output.clear(); output.resize(1,powl(input[0]+input[1],(long double)6.0));
}