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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 json_discrete_op.cpp}
Json add Operator: Example and Test
###################################
Source Code
***********
{xrst_literal
// BEGIN C++
// END C++
}
{xrst_end json_discrete_op.cpp}
*/
// BEGIN C++
# include <cppad/cppad.hpp>
namespace {
double heaviside(const double &x)
{ if( x < 0.0 )
return 0.0;
if( x == 0.0 )
return 0.5;
return 1.0;
}
CPPAD_DISCRETE_FUNCTION(double, heaviside)
}
bool discrete_op(void)
{ bool ok = true;
using CppAD::vector;
using CppAD::AD;
//
// The discrete function does not exist until its AD version is called
heaviside( CppAD::AD<double>( 0.0 ) );
//
//
// AD graph example
// node_1 : p[0]
// node_2 : x[0]
// node_3 : heaviside(p[0])
// node_4 : heaviside(p[1])
// node_5 = heaviside(p[0]) + heaviside(p[1])
// y[0] = heaviside(p[0]) + heaviside(p[1])
// use single quote to avoid having to escape double quote
std::string json =
"{\n"
" 'function_name' : 'discrete_op example',\n"
" 'op_define_vec' : [ 2, [\n"
" { 'op_code':1, 'name':'add', 'n_arg':2 } ,\n"
" { 'op_code':2, 'name':'discrete' } ]\n"
" ],\n"
" 'n_dynamic_ind' : 1,\n"
" 'n_variable_ind' : 1,\n"
" 'constant_vec' : [ 0, [ ] ],\n"
" 'op_usage_vec' : [ 3, [\n"
" [ 2, 'heaviside', 1, 1, [ 1 ] ] ,\n" // heaviside(p[0])
" [ 2, 'heaviside', 1, 1, [ 2 ] ] ,\n" // heaviside(x[0])
" [ 1, 3, 4 ] ]\n" // heaviside(p[0]) + heaviside(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) = x_0 + ( p_0 + p_1 )
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] = 0.0;
x[0] = 2.0;
//
// compute y = f(x, p)
f.new_dynamic(p);
CPPAD_TESTVECTOR(double) y = f.Forward(0, x);
//
// check result
ok &= y[0] == heaviside(p[0]) + heaviside(x[0]);
// -----------------------------------------------------------------------
// 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() == 1;
ok &= f.size_dyn_ind() == 1;
//
// set independent variables and parameters
p[0] = -2.0;
x[0] = 2.0;
//
// compute y = f(x, p)
f.new_dynamic(p);
y = f.Forward(0, x);
//
// check result
ok &= y[0] == heaviside(p[0]) + heaviside(x[0]);
//
return ok;
}
// END C++
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