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@(@\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}} }@)@ This is cppad-20221105 documentation. Here is a link to its current documentation .
speed_test: Example and test
# include <cppad/utility/speed_test.hpp>
# include <cppad/utility/vector.hpp>

namespace { // empty namespace
    using CppAD::vector;
    vector<double> a, b, c;
    void test(size_t size, size_t repeat)
    {   // setup
        a.resize(size);
        b.resize(size);
        c.resize(size);
        size_t i  = size;;
        while(i)
        {   --i;
            a[i] = double(i);
            b[i] = double(2 * i);
            c[i] = 0.0;
        }
        // operations we are timing
        while(repeat--)
        {   i = size;;
            while(i)
            {   --i;
                c[i] += std::sqrt(a[i] * a[i] + b[i] * b[i]);
            }
        }
    }
}
bool speed_test(void)
{   bool ok = true;

    // size of the test cases
    vector<size_t> size_vec(2);
    size_vec[0] = 40;
    size_vec[1] = 80;

    // minimum amount of time to run test
    double time_min = 0.5;

    // run the test cases
    vector<size_t> rate_vec(2);
    rate_vec = CppAD::speed_test(test, size_vec, time_min);

    // time per repeat loop (note counting setup or teardown)
    double time_0 = 1. / double(rate_vec[0]);
    double time_1 = 1. / double(rate_vec[1]);

    // for this case, time should be linear w.r.t size
    double check    = double(size_vec[1]) * time_0 / double(size_vec[0]);
    double rel_diff = (check - time_1) / time_1;
    ok             &= (std::fabs(rel_diff) <= .1);
    if( ! ok )
        std::cout << std::endl << "rel_diff = " << rel_diff << std::endl;

    a.clear();
    b.clear();
    c.clear();
    return ok;
}
Input File: speed/example/speed_test.cpp