\(\newcommand{\W}[1]{ \; #1 \; }\) \(\newcommand{\R}[1]{ {\rm #1} }\) \(\newcommand{\B}[1]{ {\bf #1} }\) \(\newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} }\) \(\newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} }\) \(\newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} }\) \(\newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }\)

nan.cpp

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nan: Example and Test

# include <cppad/utility/nan.hpp>
# include <vector>
# include <limits>

bool nan(void)
{  bool ok = true;

   // get a nan
   double double_zero = 0.;
   double double_nan = std::numeric_limits<double>::quiet_NaN();

   // create a simple vector with no nans
   std::vector<double> v(2);
   v[0] = double_zero;
   v[1] = double_zero;

   // check that zero is not nan
   ok &= ! CppAD::isnan(double_zero);
   ok &= ! CppAD::hasnan(v);

   // check that nan is a nan
   v[1] = double_nan;
   ok &= CppAD::isnan(double_nan);
   ok &= CppAD::hasnan(v);

   // check that nan is not equal to itself
   ok &= (double_nan != double_nan);

   return ok;
}