# include <cppad/utility/time_test.hpp>
# include <cppad/utility/vector.hpp>

namespace { // empty namespace
     using CppAD::vector;

     // size for the test
     size_t size_;

     vector<double> a, b, c;
     void test(size_t repeat)
     {     // setup
          a.resize(size_);
          b.resize(size_);
          c.resize(size_);
          size_t i  = size_;;
          while(i)
          {     --i;
               a[i] = float(i);
               b[i] = float(2 * i);
               c[i] = 0.0;
          }
          // operations we are timing
          while(repeat--)
          {     i = size_;;
               while(i)
               {     --i;
                    c[i] += std::sqrt(a[i] * a[i] + b[i] * b[i]);
               }
          }
     }

}
bool time_test(void)
{     bool ok = true;

     // minimum amount of time to run test
     double time_min = 0.5;

     // size of first test case
     size_ = 20;

     // run the first test case
     double time_first = CppAD::time_test(test, time_min);

     // size of second test case is twice as large
     size_ = 2 * size_;

     // run the second test case
     double time_second = CppAD::time_test(test, time_min);

     // for this case, time should be linear w.r.t size
     double rel_diff = 1. - 2. * time_first / time_second;
     ok             &= (std::fabs(rel_diff) <= .1);
     if( ! ok )
          std::cout << std::endl << "rel_diff = " << rel_diff  << std::endl;

     a.clear();
     b.clear();
     c.clear();
     return ok;
}