Prev Next json_div_op.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 .
Json div Operator: Example and Test

Source Code 

# include <cppad/cppad.hpp>

bool div_op(void)
{   bool ok = true;
    using CppAD::vector;
    using CppAD::AD;
    using CppAD::NearEqual;
    double eps99 = 99.0 * std::numeric_limits<double>::epsilon();
    //
    // AD graph example
    // node_1 : p[0]
    // node_2 : p[1]
    // node_3 : x[0]
    // node_4 : p[0] / p[1]
    // node_5 : x[0] / ( p[1] / p[0] )
    // y[0]   = p[0] / p[1]
    // y[1]   = x[0] / ( p[0] / p[1] )
    // use single quote to avoid having to escape double quote
    std::string json =
        "{\n"
        "   'function_name'  : 'div example',\n"
        "   'op_define_vec'  : [ 1, [\n"
        "       { 'op_code':1, 'name':'div', 'n_arg':2 } ]\n"
        "   ],\n"
        "   'n_dynamic_ind'  : 2,\n"
        "   'n_variable_ind' : 1,\n"
        "   'constant_vec'   : [ 0, [ ] ],\n"
        "   'op_usage_vec'   : [ 2, [\n"
        "       [ 1, 1, 2 ] ,\n" // p[0] / p[1]
        "       [ 1, 3, 4 ] ]\n" // x[0] / ( p[0] / p[1] )
        "   ],\n"
        "   'dependent_vec' : [ 2, [4, 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) = [ p_0 / p_1 , x_0 * p_1 / p_0 ]
    CppAD::ADFun<double> f;
    f.from_json(json);
    //
    ok &= f.Domain() == 1;
    ok &= f.Range() == 2;
    ok &= f.size_dyn_ind() == 2;
    //
    // set independent variables and parameters
    vector<double> p(2), x(1);
    p[0] = 2.0;
    p[1] = 3.0;
    x[0] = 4.0;
    //
    // compute y = f(x, p)
    f.new_dynamic(p);
    vector<double> y = f.Forward(0, x);
    //
    // check result
    ok &= NearEqual(y[0] , p[0] / p[1] , eps99, eps99 );
    ok &= NearEqual(y[1] , x[0] / ( p[0] / p[1] ), eps99, eps99 );
    // -----------------------------------------------------------------------
    // Convert to Json graph and back again
    json = f.to_json();
    // std::cout << "json = " << json;
    f.from_json(json);
    // -----------------------------------------------------------------------
    ok &= f.Domain() == 1;
    ok &= f.Range() == 2;
    ok &= f.size_dyn_ind() == 2;
    //
    // set independent variables and parameters
    p[0] = 2.0;
    p[1] = 3.0;
    x[0] = 4.0;
    //
    // compute y = f(x, p)
    f.new_dynamic(p);
    y = f.Forward(0, x);
    //
    // check result
    ok &= NearEqual(y[0] , p[0] / p[1] , eps99, eps99 );
    ok &= NearEqual(y[1] , x[0] / ( p[0] / p[1] ), eps99, eps99 );
    //
    return ok;
}
Input File: example/json/div_op.cpp