/* $Id: unary_plus.cpp 2506 2012-10-24 19:36:49Z bradbell $ */
/* --------------------------------------------------------------------------
CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-12 Bradley M. Bell
CppAD is distributed under multiple licenses. This distribution is under
the terms of the
GNU General Public License Version 3.
A copy of this license is included in the COPYING file of this distribution.
Please visit http://www.coin-or.org/CppAD/ for information on other licenses.
-------------------------------------------------------------------------- */
/*
$begin unary_plus.cpp$$
$spell
Cpp
cstddef
$$
$section AD Unary Plus Operator: Example and Test$$
$index unary plus, example$$
$index example, unary plus$$
$index test, unary plus$$
$code
$verbatim%example/unary_plus.cpp%0%// BEGIN C++%// END C++%1%$$
$$
$end
*/
// BEGIN C++
# include <cppad/cppad.hpp>
bool UnaryPlus(void)
{ bool ok = true;
using CppAD::AD;
// domain space vector
size_t n = 1;
CPPAD_TESTVECTOR(AD<double>) x(n);
x[0] = 3.;
// declare independent variables and start tape recording
CppAD::Independent(x);
// range space vector
size_t m = 1;
CPPAD_TESTVECTOR(AD<double>) y(m);
y[0] = + x[0];
// create f: x -> y and stop tape recording
CppAD::ADFun<double> f(x, y);
// check values
ok &= ( y[0] == 3. );
// forward computation of partials w.r.t. x[0]
CPPAD_TESTVECTOR(double) dx(n);
CPPAD_TESTVECTOR(double) dy(m);
size_t p = 1;
dx[0] = 1.;
dy = f.Forward(p, dx);
ok &= ( dy[0] == 1. ); // dy[0] / dx[0]
// reverse computation of dertivative of y[0]
CPPAD_TESTVECTOR(double) w(m);
CPPAD_TESTVECTOR(double) dw(n);
w[0] = 1.;
dw = f.Reverse(p, w);
ok &= ( dw[0] == 1. ); // dy[0] / dx[0]
// use a VecAD<Base>::reference object with unary plus
CppAD::VecAD<double> v(1);
AD<double> zero(0);
v[zero] = x[0];
AD<double> result = + v[zero];
ok &= (result == y[0]);
return ok;
}
// END C++