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

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;
}