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# ifndef CPPAD_FORWARD_INCLUDED
# define CPPAD_FORWARD_INCLUDED

/* --------------------------------------------------------------------------
CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-06 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.
-------------------------------------------------------------------------- */

/*
$begin Forward$$

$section Forward Mode$$

$childtable%
        omh/forward.omh%
        cppad/local/cap_taylor.hpp%
        example/forward.cpp
%$$

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

// documened after Forward but included here so easy to see
# include <cppad/local/cap_taylor.hpp>

// BEGIN CppAD namespace
namespace CppAD {

template <typename Base>
template <typename Vector>
Vector ADFun<Base>::Forward(size_t p, const Vector &up)
{       // temporary indices
        size_t i, j;

        // number of independent variables
        size_t n = ind_taddr.size();

        // number of dependent variables
        size_t m = dep_taddr.size();

        // check Vector is Simple Vector class with Base type elements
        CheckSimpleVector<Base, Vector>();

        CPPAD_ASSERT_KNOWN(
                up.size() == n,
                "Second argument to Forward does not have length equal to\n"
                "the dimension of the domain for the corresponding ADFun."
        );
        CPPAD_ASSERT_KNOWN(
                p <= taylor_per_var,
                "The number of Taylor coefficient currently stored\n"
                "in this ADFun object is less than p."
        );  

        // check if the Taylor matrix needs more columns
        if( TaylorColDim <= p )
                capacity_taylor(p + 1);
        CPPAD_ASSERT_UNKNOWN( TaylorColDim > p );

        // set the p-th order Taylor coefficients for independent variables
        for(j = 0; j < n; j++)
        {       CPPAD_ASSERT_UNKNOWN( ind_taddr[j] < totalNumVar );

                // ind_taddr[j] is operator taddr for j-th independent variable
                CPPAD_ASSERT_UNKNOWN( Rec.GetOp( ind_taddr[j] ) == InvOp );

                // It is also variable taddr for j-th independent variable
                Taylor[ind_taddr[j] * TaylorColDim + p] = up[j];
        }

        // evaluate the derivatives
        compareChange = ForwardSweep(
                true, p, totalNumVar, &Rec, TaylorColDim, Taylor
        );

        // return the p-th order Taylor coefficients for dependent variables
        Vector vp(m);
        for(i = 0; i < m; i++)
        {       CPPAD_ASSERT_UNKNOWN( dep_taddr[i] < totalNumVar );
                vp[i] = Taylor[dep_taddr[i] * TaylorColDim + p];
        }

        // now we have p + 1  Taylor coefficients per variable
        taylor_per_var = p + 1;

        return vp;
}

} // END CppAD namespace


# endif

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