/* $Id: ad_assign.hpp 2625 2012-12-23 14:34:12Z bradbell $ */
# ifndef CPPAD_AD_ASSIGN_INCLUDED
# define CPPAD_AD_ASSIGN_INCLUDED

/* --------------------------------------------------------------------------
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 
                    Eclipse Public License Version 1.0.

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 ad_assign$$
$spell
	Vec
	const
$$

$index assignment, AD$$
$index AD, assignment$$
$index assign, to AD$$
$index Base, assign to AD$$
$index VecAD, assign to AD$$

$section AD Assignment Operator$$

$head Syntax$$
$icode%y% = %x%$$

$head Purpose$$
Assigns the value in $icode x$$ to the object $icode y$$.
In either case, 

$head x$$
The argument $icode x$$ has prototype
$codei%
	const %Type% &%x%
%$$ 
where $icode Type$$ is
$codei%VecAD<%Base%>::reference%$$,
$codei%AD<%Base%>%$$,
$icode Base$$, 
or any type that has a constructor of the form
$icode%Base%(%x%)%$$.

$head y$$
The target $icode y$$ has prototype
$codei%
	AD<%Base%> %y%
%$$

$head Example$$
$children%
	example/ad_assign.cpp
%$$
The file $cref ad_assign.cpp$$ contain examples and tests of these operations.
It test returns true if it succeeds and false otherwise.

$end
------------------------------------------------------------------------------
*/

CPPAD_BEGIN_NAMESPACE

/*!
\defgroup ad_assign_hpp ad_assign.hpp
\{
\file ad_assign.hpp
AD<Base> constructors and and copy operations.
*/

/*!
\page AD_default_assign
Use default assignment operator
because they may be optimized better than the code below:
\code
template <class Base>
inline AD<Base>& AD<Base>::operator=(const AD<Base> &right)
{	value_    = right.value_;
	tape_id_  = right.tape_id_;
	taddr_    = right.taddr_;

	return *this;
}
\endcode
*/

/*!
Assignment to Base type value.

\tparam Base
Base type for this AD object.

\param b
is the Base type value being assignment to this AD object.
The tape identifier will be an invalid tape identifier,
so this object is initially a parameter.
*/
template <class Base>
inline AD<Base>& AD<Base>::operator=(const Base &b)
{	value_   = b;
	tape_id_ = 0;

	// check that this is a parameter
	CPPAD_ASSERT_UNKNOWN( Parameter(*this) );

	return *this;
}

/*!
Assignment to an ADVec<Base> element drops the vector information.

\tparam Base
Base type for this AD object.
*/
template <class Base>
inline AD<Base>& AD<Base>::operator=(const VecAD_reference<Base> &x)
{	return *this = x.ADBase(); }

/*!
Assignment from any other type, converts to Base type, and then uses assignment
from Base type.

\tparam Base
Base type for this AD object.

\tparam T
is the the type that is being assigned to AD<Base>.
There must be an assignment for Base from Type.

\param t
is the object that is being assigned to an AD<Base> object.
*/
template <class Base>
template <class T>
inline AD<Base>& AD<Base>::operator=(const T &t)
{	return *this = Base(t); }


/*! \} */
CPPAD_END_NAMESPACE
# endif
