C Source Code Corresponding to a Function: Example and Test

jit_to_csrc.cpp

@(@\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 . C Source Code Corresponding to a Function: Example and Test
to_csrc
The actual call to to_csrc is in the following section of the example below:


    f.to_csrc(ofs, c_type);

Source



# include <cstddef>
# include <iostream>
# include <fstream>
# include <map>

// DLL_EXT
# ifdef _WIN32
# define DLL_EXT ".dll"
# else
# define DLL_EXT ".so"
# endif

# include <cppad/cppad.hpp>
bool to_csrc(void)
{   bool ok = true;
    //
    using CppAD::AD;
    using CppAD::ADFun;
    using CppAD::Independent;
    using CppAD::NearEqual;
    //
    // nx, ny
    size_t nx = 2, ny = 1;
    //
    // f(x) = x_0 + x_1
    CPPAD_TESTVECTOR( AD<double> ) ax(nx), ay(ny);
    ax[0] = 0.0;
    ax[1] = 1.0;
    Independent(ax);
    ay[0] = ax[0] + ax[1];
    ADFun<double> f(ax, ay);
    f.function_name_set("f");
    //
    // csrc_file
    // created in std::filesystem::current_path
    std::string c_type    = "double";
    std::string csrc_file = "to_csrc.c";
    std::ofstream ofs;
    ofs.open(csrc_file , std::ofstream::out);
// BEGIN_TO_CSRC
    f.to_csrc(ofs, c_type);
// END_TO_CSRC
    ofs.close();
    //
    // dll_file
    // created in std::filesystem::current_path
    std::string dll_file = "jit_to_csrc" DLL_EXT;
    CPPAD_TESTVECTOR( std::string) csrc_files(1);
    csrc_files[0] = csrc_file;
    std::map< std::string, std::string > options;
    std::string err_msg = CppAD::create_dll_lib(dll_file, csrc_files, options);
    if( err_msg != "" )
    {   std::cerr << "jit_to_csrc: err_msg = " << err_msg << "\n";
        return false;
    }
    // dll_linker
    CppAD::link_dll_lib dll_linker(dll_file, err_msg);
    if( err_msg != "" )
    {   std::cerr << "jit_to_csrc: err_msg = " << err_msg << "\n";
        return false;
    }
    //
    // f_ptr
    std::string function_name = "cppad_jit_f";
    void* void_ptr = dll_linker(function_name, err_msg);
    if( err_msg != "" )
    {   std::cerr << "jit_to_csrc: err_msg = " << err_msg << "\n";
        return false;
    }
    //
    // jit_double
    using CppAD::jit_double;
    //
    // f_ptr
    jit_double f_ptr =
        reinterpret_cast<jit_double>(void_ptr);
    //
    // x, y, compare_change
    // y = f(x)
    size_t compare_change = 0;
    std::vector<double> x(nx), y(ny);
    x[0] = 0.3;
    x[1] = 0.5;
    f_ptr(nx, x.data(), ny, y.data(), &compare_change);
    //
    // ok
    ok &= compare_change == 0;
    //
    // ok
    double eps99 = 99.0 * std::numeric_limits<double>::epsilon();
    double check = x[0] + x[1];
    ok &= NearEqual(y[0], check, eps99, eps99);
    //
    return ok;
}

Input File: example/jit/to_csrc.cpp