# include <cppad/cppad.hpp>

namespace {
     bool test(void)
     {     bool ok = true;
          using CppAD::AD;
          using CppAD::NearEqual;
          using CppAD::thread_alloc;

          // domain space vector
          size_t n(1), m(1);
          CPPAD_TESTVECTOR(AD<double>) ax(n), ay(n);

          // declare independent variables and start tape recording
          ax[0]  = 1.0;
          CppAD::Independent(ax);

          // Set y = x^3, use enough variables so more that the minimal amount
          // of memory is allocated for Taylor coefficients
          ay[0] = 0.;
          for( size_t i = 0; i < 10; i++)
               ay[0] += ax[0] * ax[0] * ax[0];
          ay[0] = ay[0] / 10.;

          // create f: x -> y and stop tape recording
          // (without running zero order forward mode).
          CppAD::ADFun<double> f;
          f.Dependent(ax, ay);

          // check that this is master thread
          size_t thread = thread_alloc::thread_num();
          ok           &= thread == 0; // this should be master thread

          // The highest order forward mode calculation below is first order.
          // This corresponds to two Taylor coefficient per variable,direction
          // (orders zero and one). Preallocate memory for speed.
          size_t inuse  = thread_alloc::inuse(thread);
          f.capacity_order(2);
          ok &= thread_alloc::inuse(thread) > inuse;

          // zero order forward mode
          CPPAD_TESTVECTOR(double) x(n), y(m);
          x[0] = 0.5;
          y    = f.Forward(0, x);
          double eps = 10. * CppAD::numeric_limits<double>::epsilon();
          ok  &= NearEqual(y[0], x[0] * x[0] * x[0], eps, eps);

          // forward computation of partials w.r.t. x
          CPPAD_TESTVECTOR(double) dx(n), dy(m);
          dx[0] = 1.;
          dy    = f.Forward(1, dx);
          ok   &= NearEqual(dy[0], 3. * x[0] * x[0], eps, eps);

          // Suppose we no longer need the first order Taylor coefficients.
          inuse = thread_alloc::inuse(thread);
          f.capacity_order(1); // just keep zero order coefficients
          ok   &= thread_alloc::inuse(thread) < inuse;

          // Suppose we no longer need the zero order Taylor coefficients
          // (could have done this first and not used f.capacity_order(1)).
          inuse = thread_alloc::inuse(thread);
          f.capacity_order(0);
          ok   &= thread_alloc::inuse(thread) < inuse;

          // turn off memory holding
          thread_alloc::hold_memory(false);

          return ok;
     }
}
bool capacity_order(void)
{     bool ok = true;
     using CppAD::thread_alloc;

     // original amount of memory inuse
     size_t thread = thread_alloc::thread_num();
     ok           &= thread == 0; // this should be master thread
     size_t inuse  = thread_alloc::inuse(thread);

     // do test in separate routine so all objects are destroyed
     ok &= test();

     // check that the amount of memroy inuse has not changed
     ok &= thread_alloc::inuse(thread) == inuse;

     // Test above uses hold_memory, so return available memory
     thread_alloc::free_available(thread);

     return ok;
}