// $Id: poly.cpp 3757 2015-11-30 12:03:07Z bradbell $
/* --------------------------------------------------------------------------
CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-15 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 adolc_poly.cpp$$
$spell
	alloc
	onetape
	coef
	cppad
	hos
	Taylor
	std
	ddp
	cppad
	adouble
	std
	vector Vector
	typedef
	adolc
	Lu
	CppAD
	det
	hpp
	const
	bool
$$

$section Adolc Speed: Second Derivative of a Polynomial$$
$mindex link_poly speed$$


$head Specifications$$
See $cref link_poly$$.

$head Implementation$$

$codep */
# include <vector>
# include <adolc/adolc.h>

# include <cppad/speed/uniform_01.hpp>
# include <cppad/utility/poly.hpp>
# include <cppad/utility/vector.hpp>
# include <cppad/utility/thread_alloc.hpp>
# include "adolc_alloc_mat.hpp"

// list of possible options
extern bool global_memory, global_onetape, global_atomic, global_optimize;

bool link_poly(
	size_t                     size     ,
	size_t                     repeat   ,
	CppAD::vector<double>     &a        ,  // coefficients of polynomial
	CppAD::vector<double>     &z        ,  // polynomial argument value
	CppAD::vector<double>     &ddp      )  // second derivative w.r.t z
{
	if( global_atomic )
		return false;
	if( global_memory || global_optimize )
		return false;
	// -----------------------------------------------------
	// setup
	size_t i;
	int tag  = 0;  // tape identifier
	int keep = 0;  // do not keep forward mode results in buffer
	int m    = 1;  // number of dependent variables
	int n    = 1;  // number of independent variables
	int d    = 2;  // highest derivative degree
	double f;      // function value

	// set up for thread_alloc memory allocator (fast and checks for leaks)
	using CppAD::thread_alloc; // the allocator
	size_t capacity;           // capacity of an allocation

	// choose a vector of polynomial coefficients
	CppAD::uniform_01(size, a);

	// AD copy of the polynomial coefficients
	std::vector<adouble> A(size);
	for(i = 0; i < size; i++)
		A[i] = a[i];

	// domain and range space AD values
	adouble Z, P;

	// allocate arguments to hos_forward
	double* x0 = thread_alloc::create_array<double>(size_t(n), capacity);
	double* y0 = thread_alloc::create_array<double>(size_t(m), capacity);
	double** x = adolc_alloc_mat(size_t(n), size_t(d));
	double** y = adolc_alloc_mat(size_t(m), size_t(d));

	// Taylor coefficient for argument
	x[0][0] = 1.;  // first order
	x[0][1] = 0.;  // second order

	// ----------------------------------------------------------------------
	if( ! global_onetape ) while(repeat--)
	{	// choose an argument value
		CppAD::uniform_01(1, z);

		// declare independent variables
		trace_on(tag, keep);
		Z <<= z[0];

		// AD computation of the function value
		P = CppAD::Poly(0, A, Z);

		// create function object f : Z -> P
		P >>= f;
		trace_off();

		// set the argument value
		x0[0] = z[0];

		// evaluate the polynomial at the new argument value
		hos_forward(tag, m, n, d, keep, x0, x, y0, y);

		// second derivative is twice second order Taylor coef
		ddp[0] = 2. * y[0][1];
	}
	else
	{
		// choose an argument value
		CppAD::uniform_01(1, z);

		// declare independent variables
		trace_on(tag, keep);
		Z <<= z[0];

		// AD computation of the function value
		P = CppAD::Poly(0, A, Z);

		// create function object f : Z -> P
		P >>= f;
		trace_off();

		while(repeat--)
		{	// get the next argument value
			CppAD::uniform_01(1, z);
			x0[0] = z[0];

			// evaluate the polynomial at the new argument value
			hos_forward(tag, m, n, d, keep, x0, x, y0, y);

			// second derivative is twice second order Taylor coef
			ddp[0] = 2. * y[0][1];
		}
	}
	// ------------------------------------------------------
	// tear down
	adolc_free_mat(x);
	adolc_free_mat(y);
	thread_alloc::delete_array(x0);
	thread_alloc::delete_array(y0);

	return true;
}
/* $$
$end
*/
