// [[Rcpp::depends(BH)]]
/*!
 * 
 *
 * \brief       dot-product of vectors
 *
 * \author      O. Krause
 * \date        2013
 *
 *
 * \par Copyright 1995-2015 Shark Development Team
 * 
 * <BR><HR>
 * This file is part of Shark.
 * <http://image.diku.dk/shark/>
 * 
 * Shark is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published 
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Shark is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with Shark.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
#ifndef SHARK_LINALG_BLAS_KERNELS_DOT_HPP
#define SHARK_LINALG_BLAS_KERNELS_DOT_HPP

#include "default/dot.hpp"

//~ #ifdef SHARK_USE_CBLAS 
//~ #include "cblas/dot.hpp" // not faster in many cases, the compiler optimizes quite well.
//~ #else
// if no bindings are included, we have to provide the default has_optimized_dot
// otherwise the binding will take care of this
namespace shark { namespace blas { namespace bindings{
template<class V1, class V2,class result_type>
struct  has_optimized_dot
: public boost::mpl::false_{};
}}}
//~ #endif
	
namespace shark { namespace blas {namespace kernels{
	
///\brief Well known dot-product r=<e1,e2>=sum_i e1_i*e2_i.
///
/// If bindings are included and the vector combination allows for a specific binding
/// to be applied, the binding is called automatically from {binding}/dot.h
/// otherwise default/dot.h is used which is fully implemented for all dense/sparse combinations.
/// if a combination is optimized, bindings::has_optimized_dot<E1,E2,R>::type evaluates to boost::mpl::true_
/// The kernels themselves are implemented in blas::bindings::dot.
template<class E1, class E2,class result_type>
void dot(
	vector_expression<E1> const& e1,
	vector_expression<E2> const& e2,
	result_type& result
) {
	SIZE_CHECK(e1().size() == e2().size());
	
	bindings::dot(
		e1, e2,result,
		typename bindings::has_optimized_dot<E1,E2,result_type>::type()
	);
}

}}}
#endif
