ad_output.cpp

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AD Output Operator: Example and Test

# include <cppad/cppad.hpp>

# include <sstream>  // std::ostringstream
# include <string>   // std::string
# include <iomanip>  // std::setprecision, setw, setfill, right

namespace {
   template <class S>
   void set_ostream(S &os)
   {  os
      << std::setprecision(4) // 4 digits of precision
      << std::setw(6)         // 6 characters per field
      << std::setfill(' ')    // fill with spaces
      << std::right;          // adjust value to the right
   }
}

bool ad_output(void)
{  bool ok = true;

   // This output stream is an ostringstream for testing purposes.
   // You can use << with other types of streams; i.e., std::cout.
   std::ostringstream stream;

   // ouput an AD<double> object
   CppAD::AD<double>  pi = 4. * atan(1.); // 3.1415926536
   set_ostream(stream);
   stream << pi;

   // ouput a VecAD<double>::reference object
   CppAD::VecAD<double> v(1);
   CppAD::AD<double> zero(0);
   v[zero]   = exp(1.);                  // 2.7182818285
   set_ostream(stream);
   stream << v[zero];

   // convert output from stream to string
   std::string str = stream.str();

   // check the output
   ok      &= (str == " 3.142 2.718");

   return ok;
}