--- /dev/null
+/* -*- 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
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