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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 graph_discrete_op.cpp}
C++ AD Graph add Operator: Example and Test
###########################################
Source Code
***********
{xrst_literal
// BEGIN C++
// END C++
}
{xrst_end graph_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 std::string;
//
// 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])
//
// C++ graph object
CppAD::cpp_graph graph_obj;
//
// operator being used
CppAD::graph::graph_op_enum op_enum;
//
// set scalars
graph_obj.function_name_set("discrete_op example");
size_t n_dynamic_ind = 1;
graph_obj.n_dynamic_ind_set(n_dynamic_ind);
size_t n_variable_ind = 1;
graph_obj.n_variable_ind_set(n_variable_ind);
//
// name_index corresponding to heaviside function
size_t name_index = graph_obj.discrete_name_vec_size();
graph_obj.discrete_name_vec_push_back("heaviside");
//
// heaviside(p[0])
op_enum = CppAD::graph::discrete_graph_op;
graph_obj.operator_vec_push_back(op_enum);
graph_obj.operator_arg_push_back(name_index); // name_index
graph_obj.operator_arg_push_back(1); // node arg
//
// heaviside(x[0])
graph_obj.operator_vec_push_back(op_enum);
graph_obj.operator_arg_push_back(name_index); // name_index
graph_obj.operator_arg_push_back(2); // node arg
//
// heaviside(p[0]) + heaviside(x[0])
op_enum = CppAD::graph::add_graph_op;
graph_obj.operator_vec_push_back(op_enum);
graph_obj.operator_arg_push_back(3); // first node arg
graph_obj.operator_arg_push_back(4); // second node arg
//
// y[0] = heaviside(p[0]) + heaviside(x[0])
graph_obj.dependent_vec_push_back(5);
//
// f(x, p) = heaviside(p[0]) + heaviside(x[0])
CppAD::ADFun<double> f;
f.from_graph(graph_obj);
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 function to graph and back again
f.to_graph(graph_obj);
f.from_graph(graph_obj);
// -----------------------------------------------------------------------
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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