-/* -*- C++ -*- ------------------------------------------------------------
-
-Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
-
-The Configurable Math Library (CML) is distributed under the terms of the
-Boost Software License, v1.0 (see cml/LICENSE for details).
-
- *-----------------------------------------------------------------------*/
-/** @file
- * @brief Multiply two matrices.
- *
- * @todo Does it make sense to put mat-mat multiplication as a node into the
- * expression tree?
- *
- * @internal This does not need to return an expression type, since the
- * temporary generation for the matrix result is handled automatically by the
- * compiler. i.e. when used in an expression, the result is automatically
- * included in the expression tree as a temporary by the compiler.
- */
-
-#ifndef matrix_mul_h
-#define matrix_mul_h
-
-#include <cml/et/size_checking.h>
-#include <cml/matrix/matrix_expr.h>
-
-/* This is used below to create a more meaningful compile-time error when
- * mul is not provided with matrix or MatrixExpr arguments:
- */
-struct mul_expects_matrix_args_error;
-
-/* This is used below to create a more meaningful compile-time error when
- * fixed-size arguments to mul() have the wrong size:
- */
-struct mul_expressions_have_wrong_size_error;
-
-namespace cml {
-namespace detail {
-
-/** Verify the sizes of the argument matrices for matrix multiplication.
- *
- * @returns a matrix_size containing the size of the resulting matrix.
- */
-template<typename LeftT, typename RightT> inline matrix_size
-MatMulCheckedSize(const LeftT&, const RightT&, fixed_size_tag)
-{
- CML_STATIC_REQUIRE_M(
- ((size_t)LeftT::array_cols == (size_t)RightT::array_rows),
- mul_expressions_have_wrong_size_error);
- return matrix_size(LeftT::array_rows,RightT::array_cols);
-}
-
-/** Verify the sizes of the argument matrices for matrix multiplication.
- *
- * @returns a matrix_size containing the size of the resulting matrix.
- */
-template<typename LeftT, typename RightT> inline matrix_size
-MatMulCheckedSize(const LeftT& left, const RightT& right, dynamic_size_tag)
-{
- matrix_size left_N = left.size(), right_N = right.size();
- et::GetCheckedSize<LeftT,RightT,dynamic_size_tag>()
- .equal_or_fail(left_N.second, right_N.first); /* cols,rows */
- return matrix_size(left_N.first, right_N.second); /* rows,cols */
-}
-
-
-/** Matrix multiplication.
- *
- * Computes C = A x B (O(N^3), non-blocked algorithm).
- */
-template<class LeftT, class RightT>
-inline typename et::MatrixPromote<
- typename et::ExprTraits<LeftT>::result_type,
- typename et::ExprTraits<RightT>::result_type
->::temporary_type
-mul(const LeftT& left, const RightT& right)
-{
- /* Shorthand: */
- typedef et::ExprTraits<LeftT> left_traits;
- typedef et::ExprTraits<RightT> right_traits;
- typedef typename left_traits::result_type left_result;
- typedef typename right_traits::result_type right_result;
-
- /* First, require matrix expressions: */
- CML_STATIC_REQUIRE_M(
- (et::MatrixExpressions<LeftT,RightT>::is_true),
- mul_expects_matrix_args_error);
- /* Note: parens are required here so that the preprocessor ignores the
- * commas.
- */
-
- /* Deduce size type to ensure that a run-time check is performed if
- * necessary:
- */
- typedef typename et::MatrixPromote<
- typename left_traits::result_type,
- typename right_traits::result_type
- >::type result_type;
- typedef typename result_type::size_tag size_tag;
-
- /* Require that left has the same number of columns as right has rows.
- * This automatically checks fixed-size matrices at compile time, and
- * throws at run-time if the sizes don't match:
- */
- matrix_size N = detail::MatMulCheckedSize(left, right, size_tag());
-
- /* Create an array with the right size (resize() is a no-op for
- * fixed-size matrices):
- */
- result_type C;
- cml::et::detail::Resize(C, N);
-
- /* XXX Specialize this for fixed-size matrices: */
- typedef typename result_type::value_type value_type;
- for(size_t i = 0; i < left.rows(); ++i) { /* rows */
- for(size_t j = 0; j < right.cols(); ++j) { /* cols */
- value_type sum(left(i,0)*right(0,j));
- for(size_t k = 1; k < right.rows(); ++k) {
- sum += (left(i,k)*right(k,j));
- }
- C(i,j) = sum;
- }
- }
-
- return C;
-}
-
-} // namespace detail
-
-
-/** operator*() for two matrices. */
-template<typename E1, class AT1, typename L1,
- typename E2, class AT2, typename L2,
- typename BO>
-inline typename et::MatrixPromote<
- matrix<E1,AT1,BO,L1>, matrix<E2,AT2,BO,L2>
->::temporary_type
-operator*(const matrix<E1,AT1,BO,L1>& left,
- const matrix<E2,AT2,BO,L2>& right)
-{
- return detail::mul(left,right);
-}
-
-/** operator*() for a matrix and a MatrixXpr. */
-template<typename E, class AT, typename BO, typename L, typename XprT>
-inline typename et::MatrixPromote<
- matrix<E,AT,BO,L>, typename XprT::result_type
->::temporary_type
-operator*(const matrix<E,AT,BO,L>& left,
- const et::MatrixXpr<XprT>& right)
-{
- /* Generate a temporary, and compute the right-hand expression: */
- typedef typename et::MatrixXpr<XprT>::temporary_type expr_tmp;
- expr_tmp tmp;
- cml::et::detail::Resize(tmp,right.rows(),right.cols());
- tmp = right;
-
- return detail::mul(left,tmp);
-}
-
-/** operator*() for a MatrixXpr and a matrix. */
-template<typename XprT, typename E, class AT, typename BO, typename L>
-inline typename et::MatrixPromote<
- typename XprT::result_type , matrix<E,AT,BO,L>
->::temporary_type
-operator*(const et::MatrixXpr<XprT>& left,
- const matrix<E,AT,BO,L>& right)
-{
- /* Generate a temporary, and compute the left-hand expression: */
- typedef typename et::MatrixXpr<XprT>::temporary_type expr_tmp;
- expr_tmp tmp;
- cml::et::detail::Resize(tmp,left.rows(),left.cols());
- tmp = left;
-
- return detail::mul(tmp,right);
-}
-
-/** operator*() for two MatrixXpr's. */
-template<typename XprT1, typename XprT2>
-inline typename et::MatrixPromote<
- typename XprT1::result_type, typename XprT2::result_type
->::temporary_type
-operator*(const et::MatrixXpr<XprT1>& left,
- const et::MatrixXpr<XprT2>& right)
-{
- /* Generate temporaries and compute expressions: */
- typedef typename et::MatrixXpr<XprT1>::temporary_type left_tmp;
- left_tmp ltmp;
- cml::et::detail::Resize(ltmp,left.rows(),left.cols());
- ltmp = left;
-
- typedef typename et::MatrixXpr<XprT2>::temporary_type right_tmp;
- right_tmp rtmp;
- cml::et::detail::Resize(rtmp,right.rows(),right.cols());
- rtmp = right;
-
- return detail::mul(ltmp,rtmp);
-}
-
-} // namespace cml
-
-#endif
-
-// -------------------------------------------------------------------------
-// vim:ft=cpp