/* $Id: mul_op.hpp 1680 2010-04-24 22:37:01Z bradbell $ */
# ifndef CPPAD_MUL_OP_INCLUDED
# define CPPAD_MUL_OP_INCLUDED

/* --------------------------------------------------------------------------
CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-10 Bradley M. Bell

CppAD is distributed under multiple licenses. This distribution is under
the terms of the 
                    Common 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.
-------------------------------------------------------------------------- */

CPPAD_BEGIN_NAMESPACE
/*!
\file mul_op.hpp
Forward and reverse mode calculations for z = x * y.
*/

// --------------------------- Mulvv -----------------------------------------
/*!
Compute forward mode Taylor coefficients for result of op = MulvvOp.

The C++ source code corresponding to this operation is
\verbatim
	z = x * y
\endverbatim
In the documentation below,
this operations is for the case where both x and y are variables
and the argument \a parameter is not used.

\copydetails forward_binary_op
*/

template <class Base>
inline void forward_mulvv_op(
	size_t        d           , 
	size_t        i_z         ,
	const size_t* arg         ,
	const Base*   parameter   ,
	size_t        nc_taylor   ,
	Base*         taylor      )
{
	// check assumptions
	CPPAD_ASSERT_UNKNOWN( NumArg(MulvvOp) == 2 );
	CPPAD_ASSERT_UNKNOWN( NumRes(MulvvOp) == 1 );
	CPPAD_ASSERT_UNKNOWN( arg[0] < i_z );
	CPPAD_ASSERT_UNKNOWN( arg[1] < i_z );
	CPPAD_ASSERT_UNKNOWN( d < nc_taylor );

	// Taylor coefficients corresponding to arguments and result
	Base* x = taylor + arg[0] * nc_taylor;
	Base* y = taylor + arg[1] * nc_taylor;
	Base* z = taylor + i_z    * nc_taylor;

	size_t k;
	z[d] = Base(0);
	for(k = 0; k <= d; k++)
		z[d] += x[d-k] * y[k];
}

/*!
Compute zero order forward mode Taylor coefficients for result of op = MulvvOp.

The C++ source code corresponding to this operation is
\verbatim
	z = x * y
\endverbatim
In the documentation below,
this operations is for the case where both x and y are variables
and the argument \a parameter is not used.

\copydetails forward_binary_op_0
*/

template <class Base>
inline void forward_mulvv_op_0(
	size_t        i_z         ,
	const size_t* arg         ,
	const Base*   parameter   ,
	size_t        nc_taylor   ,
	Base*         taylor      )
{
	// check assumptions
	CPPAD_ASSERT_UNKNOWN( NumArg(MulvvOp) == 2 );
	CPPAD_ASSERT_UNKNOWN( NumRes(MulvvOp) == 1 );
	CPPAD_ASSERT_UNKNOWN( arg[0] < i_z );
	CPPAD_ASSERT_UNKNOWN( arg[1] < i_z );

	// Taylor coefficients corresponding to arguments and result
	Base* x = taylor + arg[0] * nc_taylor;
	Base* y = taylor + arg[1] * nc_taylor;
	Base* z = taylor + i_z    * nc_taylor;

	z[0] = x[0] * y[0];
}

/*!
Compute reverse mode partial derivatives for result of op = MulvvOp.

The C++ source code corresponding to this operation is
\verbatim
	z = x * y
\endverbatim
In the documentation below,
this operations is for the case where both x and y are variables
and the argument \a parameter is not used.

\copydetails reverse_binary_op
*/

template <class Base>
inline void reverse_mulvv_op(
	size_t        d           , 
	size_t        i_z         ,
	const size_t* arg         ,
	const Base*   parameter   ,
	size_t        nc_taylor   ,
	const Base*   taylor      ,
	size_t        nc_partial  ,
	Base*         partial     )
{
	// check assumptions
	CPPAD_ASSERT_UNKNOWN( NumArg(MulvvOp) == 2 );
	CPPAD_ASSERT_UNKNOWN( NumRes(MulvvOp) == 1 );
	CPPAD_ASSERT_UNKNOWN( arg[0] < i_z );
	CPPAD_ASSERT_UNKNOWN( arg[1] < i_z );
	CPPAD_ASSERT_UNKNOWN( d < nc_taylor );
	CPPAD_ASSERT_UNKNOWN( d < nc_partial );

	// Arguments
	const Base* x  = taylor + arg[0] * nc_taylor;
	const Base* y  = taylor + arg[1] * nc_taylor;

	// Partial derivatives corresponding to arguments and result
	Base* px = partial + arg[0] * nc_partial;
	Base* py = partial + arg[1] * nc_partial;
	Base* pz = partial + i_z    * nc_partial;


	// number of indices to access
	size_t j = d + 1;
	size_t k;
	while(j)
	{	--j;
		for(k = 0; k <= j; k++)
		{	
			px[j-k] += pz[j] * y[k];
			py[k]   += pz[j] * x[j-k];
		}
	}
}
// --------------------------- Mulpv -----------------------------------------
/*!
Compute forward mode Taylor coefficients for result of op = MulpvOp.

The C++ source code corresponding to this operation is
\verbatim
	z = x * y
\endverbatim
In the documentation below,
this operations is for the case where x is a parameter and y is a variable.

\copydetails forward_binary_op
*/

template <class Base>
inline void forward_mulpv_op(
	size_t        d           , 
	size_t        i_z         ,
	const size_t* arg         ,
	const Base*   parameter   ,
	size_t        nc_taylor   ,
	Base*         taylor      )
{
	// check assumptions
	CPPAD_ASSERT_UNKNOWN( NumArg(MulpvOp) == 2 );
	CPPAD_ASSERT_UNKNOWN( NumRes(MulpvOp) == 1 );
	CPPAD_ASSERT_UNKNOWN( arg[1] < i_z );
	CPPAD_ASSERT_UNKNOWN( d < nc_taylor );

	// Taylor coefficients corresponding to arguments and result
	Base* y = taylor + arg[1] * nc_taylor;
	Base* z = taylor + i_z    * nc_taylor;

	// Paraemter value
	Base x = parameter[ arg[0] ];

	z[d] = x * y[d];
}
/*!
Compute zero order forward mode Taylor coefficient for result of op = MulpvOp.

The C++ source code corresponding to this operation is
\verbatim
	z = x * y
\endverbatim
In the documentation below,
this operations is for the case where x is a parameter and y is a variable.

\copydetails forward_binary_op_0
*/

template <class Base>
inline void forward_mulpv_op_0(
	size_t        i_z         ,
	const size_t* arg         ,
	const Base*   parameter   ,
	size_t        nc_taylor   ,
	Base*         taylor      )
{
	// check assumptions
	CPPAD_ASSERT_UNKNOWN( NumArg(MulpvOp) == 2 );
	CPPAD_ASSERT_UNKNOWN( NumRes(MulpvOp) == 1 );
	CPPAD_ASSERT_UNKNOWN( arg[1] < i_z );

	// Paraemter value
	Base x = parameter[ arg[0] ];

	// Taylor coefficients corresponding to arguments and result
	Base* y = taylor + arg[1] * nc_taylor;
	Base* z = taylor + i_z    * nc_taylor;

	z[0] = x * y[0];
}

/*!
Compute reverse mode partial derivative for result of op = MulpvOp.

The C++ source code corresponding to this operation is
\verbatim
	z = x * y
\endverbatim
In the documentation below,
this operations is for the case where x is a parameter and y is a variable.

\copydetails reverse_binary_op
*/

template <class Base>
inline void reverse_mulpv_op(
	size_t        d           , 
	size_t        i_z         ,
	const size_t* arg         ,
	const Base*   parameter   ,
	size_t        nc_taylor   ,
	const Base*   taylor      ,
	size_t        nc_partial  ,
	Base*         partial     )
{
	// check assumptions
	CPPAD_ASSERT_UNKNOWN( NumArg(MulvvOp) == 2 );
	CPPAD_ASSERT_UNKNOWN( NumRes(MulvvOp) == 1 );
	CPPAD_ASSERT_UNKNOWN( arg[1] < i_z );
	CPPAD_ASSERT_UNKNOWN( d < nc_taylor );
	CPPAD_ASSERT_UNKNOWN( d < nc_partial );

	// Arguments
	Base x  = parameter[ arg[0] ];

	// Partial derivatives corresponding to arguments and result
	Base* py = partial + arg[1] * nc_partial;
	Base* pz = partial + i_z    * nc_partial;

	// number of indices to access
	size_t j = d + 1;
	while(j)
	{	--j;
		py[j] += pz[j] * x;
	}
}


CPPAD_END_NAMESPACE
# endif
