Tiny Vector Matrix library using Expression Templates

00001 /*
00002  * Tiny Vector Matrix Library
00003  * Dense Vector Matrix Libary of Tiny size using Expression Templates
00004  *
00005  * Copyright (C) 2001 - 2007 Olaf Petzold <opetzold@users.sourceforge.net>
00006  *
00007  * This library is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * This library is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with this library; if not, write to the Free Software
00019  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00020  *
00021  * $Id: Gemm.h,v 1.12 2007-06-23 15:58:59 opetzold Exp $
00022  */
00023 
00024 #ifndef TVMET_LOOP_GEMM_H
00025 #define TVMET_LOOP_GEMM_H
00026 
00027 namespace tvmet {
00028 
00029 namespace loop {
00030 
00031 
00057 template<std::size_t Rows1, std::size_t Cols1,
00058    std::size_t Cols2>
00059 class gemm
00060 {
00061   gemm(const gemm&);
00062   gemm& operator=(const gemm&);
00063 
00064 private:
00065   enum {
00066     count   = Cols1,
00067     N     = (count+7)/8
00068   };
00069 
00070 public:
00071   gemm() { }
00072 
00073 public:
00074   template<class E1, class E2>
00075   static inline
00076   typename PromoteTraits<
00077     typename E1::value_type,
00078     typename E2::value_type
00079     >::value_type
00080   prod(const E1& lhs, const E2& rhs, std::size_t i, std::size_t j) {
00081     typename PromoteTraits<
00082       typename E1::value_type,
00083       typename E2::value_type
00084     >::value_type         sum(0);
00085     std::size_t         k(0);
00086     std::size_t         n(N);
00087 
00088     // Duff's device
00089     switch(count % 8) {
00090     case 0: do { sum += lhs(i, k) * rhs(k, j); ++k;
00091     case 7:      sum += lhs(i, k) * rhs(k, j); ++k;
00092     case 6:      sum += lhs(i, k) * rhs(k, j); ++k;
00093     case 5:      sum += lhs(i, k) * rhs(k, j); ++k;
00094     case 4:      sum += lhs(i, k) * rhs(k, j); ++k;
00095     case 3:      sum += lhs(i, k) * rhs(k, j); ++k;
00096     case 2:      sum += lhs(i, k) * rhs(k, j); ++k;
00097     case 1:      sum += lhs(i, k) * rhs(k, j); ++k;
00098             } while(--n != 0);
00099     }
00100 
00101     return sum;
00102   }
00103 };
00104 
00105 
00106 } // namespace loop
00107 
00108 } // namespace tvmet
00109 
00110 #endif /* TVMET_LOOP_GEMM_H */
00111 
00112 // Local Variables:
00113 // mode:C++
00114 // tab-width:8
00115 // End:
include/tvmet/loop/Gemm.h
