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Up-> CppAD ADFun other_adfun json_ad_graph json_graph_op json_print_op.cpp

json_print_op.cpp

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# include <cppad/cppad.hpp>

bool print_op(void)
{   bool ok = true;
    using std::string;
    std::stringstream stream_out;
    double eps99 = 99.0 * std::numeric_limits<double>::epsilon();
    //
    // AD graph example
    // node_1 : p[0]
    // node_2 : x[0]
    //        : print(p[0], "p[0] = ", p[0], "\n")
    //        : print(x[0], "x[0] = ", x[0], "\n")
    // node_3 : log(p[0])
    // node_4 : log(x[0])
    // node_5 = log(p[0]) + log(x[0])
    // y[0]   = log(p[0]) + log(x[0])
    // use single quote to avoid having to escape double quote
    std::string json =
        "{\n"
        "   'function_name'  : 'print_op example',\n"
        "   'op_define_vec'  : [ 3, [\n"
        "       { 'op_code':1, 'name':'print'              } ,\n"
        "       { 'op_code':2, 'name':'log',     'n_arg':1 } ,\n"
        "       { 'op_code':3, 'name':'add',     'n_arg':2 } ]\n"
        "   ],\n"
        "   'n_dynamic_ind'  : 1,\n"
        "   'n_variable_ind' : 1,\n"
        "   'constant_vec'   : [ 0, [ ] ],\n"
        "   'op_usage_vec'   : [ 5, [\n"
        "       [ 1, 'p[0] = ', '\n', 0, 2, [1, 1 ] ] ,\n" // first print
        "       [ 1, 'x[0] = ', '\n', 0, 2, [2, 2 ] ] ,\n" // second print
        "       [ 2, 1    ] ,\n" // log(p[0])
        "       [ 2, 2    ] ,\n" // log(x[0])
        "       [ 3, 3, 4 ] ]\n" // log(p[0]) + log(x[0])
        "   ],\n"
        "   'dependent_vec' : [ 1, [5] ] \n"
        "}\n";
    // Convert the single quote to double quote
    for(size_t i = 0; i < json.size(); ++i)
        if( json[i] == '\'' ) json[i] = '"';
    //
    // f(x, p) = log(p[0]) + log(x[0])
    CppAD::ADFun<double> f;
    f.from_json(json);
    ok &= f.Domain() == 1;
    ok &= f.Range() == 1;
    ok &= f.size_dyn_ind() == 1;
    //
    // set independent variables and parameters
    CPPAD_TESTVECTOR(double) p(1), x(1);
    p[0] = 1.0;
    x[0] = 2.0;
    //
    // compute y = f(x, p)
    f.new_dynamic(p);
    CPPAD_TESTVECTOR(double) y = f.Forward(0, x, stream_out);
    //
    // check result
    ok &= stream_out.str() == "";
    double check = std::log(p[0]) + std::log(x[0]);
    ok &= CppAD::NearEqual(y[0], check, eps99, eps99);
    //
    // -----------------------------------------------------------------------
    // Convert function to json and back again
    json = f.to_json();
    // std::cout << json;
    f.from_json(json);
    // -----------------------------------------------------------------------
    ok &= f.Domain() == 1;
    ok &= f.Range() == 1;
    ok &= f.size_dyn_ind() == 1;
    //
    // set independent variables and parameters
    p[0] = 1.0;
    x[0] = -2.0;
    //
    // compute y = f(x, p)
    f.new_dynamic(p);
    f.check_for_nan(false);
    y = f.Forward(0, x, stream_out);
    //
    // check result
    ok &= stream_out.str() == "x[0] = -2\n";
    ok &= std::isnan(y[0]);
    //
    return ok;
}