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// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
// SPDX-FileCopyrightText: Bradley M. Bell <bradbell@seanet.com>
// SPDX-FileContributor: 2003-22 Bradley M. Bell
// ----------------------------------------------------------------------------
/*
{xrst_begin to_json.cpp}
Convert an ADFun Object to a Json AD Graph: Example and Test
############################################################
Source Code
***********
{xrst_literal
// BEGIN C++
// END C++
}
{xrst_end to_json.cpp}
*/
// BEGIN C++
# include <cppad/cppad.hpp>
bool to_json(void)
{ bool ok = true;
using CppAD::vector;
using CppAD::AD;
//
// An AD graph example
// node_1 : x[0]
// node_2 : x[1]
// node_3 : x[0] + x[1]
// node_4 : (x[0] + x[1]) * x[1]
// y[0] = (x[0] + x[1]) * x[1]
// use single quote to avoid having to escape double quote
std::string json =
"{\n"
" 'function_name' : 'to_json example',\n"
" 'op_define_vec' : [ 2, [\n"
" { 'op_code':1, 'name':'add', 'n_arg':2 } ,\n"
" { 'op_code':2, 'name':'mul', 'n_arg':2 } ]\n"
" ],\n"
" 'n_dynamic_ind' : 0,\n"
" 'n_variable_ind' : 2,\n"
" 'constant_vec' : [ 0, [ ] ],\n"
" 'op_usage_vec' : [ 2, [\n"
" [ 1, 1, 2 ] ,\n"
" [ 2, 3, 2 ] ]\n"
" ],\n"
" 'dependent_vec' : [ 1, [4] ] \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) = (x_0 + x_1) * x_1
CppAD::ADFun< AD<double> > af;
af.from_json(json);
ok &= af.Domain() == 2;
ok &= af.Range() == 1;
//
// Declare independent variables for a new recording
vector< AD<double> > ax(2);
ax[0] = 1.0;
ax[1] = 2.0;
CppAD::Independent(ax);
//
// Compute f(x)
af.Forward(0, ax);
//
// Compute z = f'(x)
vector< AD<double> > aw(1), az(2);
aw[0] = 1.0;
az = af.Reverse(1, aw);
//
// define g(x) = f'(x)
CppAD::ADFun<double> g(ax, az);
// ------------------------------------------------------------------------
// Convert to Json graph and back
json = g.to_json();
// std::cout << json;
g.from_json(json);
// ------------------------------------------------------------------------
//
// Evaluate function corresponding to g
vector<double> x(2), z(2);
x[0] = 3.0;
x[1] = 4.0;
z = g.Forward(0, x);
//
// should be derivative of f
ok &= z[0] == x[1];
ok &= z[1] == x[0] + 2.0 * x[1];
//
return ok;
}
// END C++
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