# include <cppad/cppad.hpp>

bool Compare(void)
{     bool ok = true;
     using CppAD::AD;
     using CppAD::NearEqual;
     double eps99 = 99.0 * std::numeric_limits<double>::epsilon();

     // declare independent variables and start tape recording
     size_t n  = 2;
     double x0 = 0.5;
     double x1 = 1.5;
     CPPAD_TESTVECTOR(AD<double>) x(n);
     x[0]      = x0;
     x[1]      = x1;
     CppAD::Independent(x);

     // some binary comparision operations
     AD<double> p;
     if( x[0] < x[1] )
          p = x[0];   // values in x choose this case
     else     p = x[1];
     if( x[0] <= x[1] )
          p *= x[0];  // values in x choose this case
     else     p *= x[1];
     if( x[0] >  x[1] )
          p *= x[0];
     else     p *= x[1];  // values in x choose this case
     if( x[0] >= x[1] )
          p *= x[0];
     else     p *= x[1];  // values in x choose this case
     if( x[0] == x[1] )
          p *= x[0];
     else     p *= x[1];  // values in x choose this case
     if( x[0] != x[1] )
          p *= x[0];  // values in x choose this case
     else     p *= x[1];

     // dependent variable vector
     size_t m = 1;
     CPPAD_TESTVECTOR(AD<double>) y(m);
     y[0] = p;

     // create f: x -> y and stop tape recording
     CppAD::ADFun<double> f(x, y);

     // check value
     ok &= NearEqual(y[0] , x0*x0*x1*x1*x1*x0, eps99, eps99);

     // forward computation of partials w.r.t. x[0]
     CPPAD_TESTVECTOR(double) dx(n);
     CPPAD_TESTVECTOR(double) dy(m);
     dx[0] = 1.;
     dx[1] = 0.;
     dy    = f.Forward(1, dx);
     ok   &= NearEqual(dy[0], 3.*x0*x0*x1*x1*x1, eps99, eps99);

     // forward computation of partials w.r.t. x[1]
     dx[0] = 0.;
     dx[1] = 1.;
     dy    = f.Forward(1, dx);
     ok   &= NearEqual(dy[0], 3.*x0*x0*x1*x1*x0, eps99, eps99);

     // reverse computation of derivative of y[0]
     CPPAD_TESTVECTOR(double)  w(m);
     CPPAD_TESTVECTOR(double) dw(n);
     w[0]  = 1.;
     dw    = f.Reverse(1, w);
     ok   &= NearEqual(dw[0], 3.*x0*x0*x1*x1*x1, eps99, eps99);
     ok   &= NearEqual(dw[1], 3.*x0*x0*x1*x1*x0, eps99, eps99);

     return ok;
}