Eval.h

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: Eval.h,v 1.13 2007-06-23 15:58:59 opetzold Exp $
00022  */
00023 
00024 #ifndef TVMET_XPR_EVAL_H
00025 #define TVMET_XPR_EVAL_H
00026 
00027 namespace tvmet {
00028 
00029 
00030 /**
00031  * \class XprEval Eval.h "tvmet/xpr/Eval.h"
00032  * \brief evaluate the expression
00033  *
00034  * Since we can't overwrite the ? operator we have to write a wrapper
00035  * for expression like return v1>v2 ? true : false
00036  */
00037 template<class E1, class E2, class E3>
00038 class XprEval
00039   : public TvmetBase< XprEval<E1, E2, E3> >
00040 {
00041 public:
00042   typedef E1                         expr1_type;
00043   typedef E2                         expr2_type;
00044   typedef E3                         expr3_type;
00045 
00046   typedef typename expr2_type::value_type         value2_type;
00047   typedef typename expr3_type::value_type         value3_type;
00048 
00049   typedef typename
00050   PromoteTraits<value2_type, value3_type>::value_type     value_type;
00051 
00052 public:
00053   /** Complexity Counter */
00054   enum {
00055     ops_expr1 = E1::ops,
00056     ops_expr2 = E2::ops,
00057     ops_expr3 = E3::ops,
00058     ops = ops_expr1    // only (e1 op e2) are evaluated
00059   };
00060 
00061 private:
00062   XprEval();
00063   XprEval& operator=(const XprEval<expr1_type, expr2_type, expr3_type>&);
00064 
00065 public:
00066   /** Constructor */
00067   explicit XprEval(const expr1_type& e1, const expr2_type& e2, const expr3_type& e3)
00068     : m_expr1(e1), m_expr2(e2), m_expr3(e3)
00069   { }
00070 
00071   /** Copy Constructor. Not explicit! */
00072 #if defined(TVMET_OPTIMIZE_XPR_MANUAL_CCTOR)
00073   XprEval(const XprEval& rhs)
00074     : m_expr1(rhs.m_expr1), m_expr2(rhs.m_expr2), m_expr3(rhs.m_expr3)
00075   { }
00076 #endif
00077 
00078 public: //access
00079   /** index operator for vectors. */
00080   value_type operator()(std::size_t i) const {
00081     return m_expr1(i) ? m_expr2(i) : m_expr3(i);
00082   }
00083 
00084   /** index operator for matrizes. */
00085   value_type operator()(std::size_t i, std::size_t j) const {
00086     return m_expr1(i, j) ? m_expr2(i, j) : m_expr3(i, j);
00087   }
00088 
00089 public: // debugging Xpr parse tree
00090   void print_xpr(std::ostream& os, std::size_t l=0) const {
00091     os << IndentLevel(l++)
00092        << "XprEval[" << ops << ", ("
00093        << ops_expr1 << ", " << ops_expr2 << ", " << ops_expr3 << ")]<"
00094        << std::endl;
00095     m_expr1.print_xpr(os, l);
00096     m_expr2.print_xpr(os, l);
00097     m_expr3.print_xpr(os, l);
00098     os << IndentLevel(--l)
00099        << ">," << std::endl;
00100   }
00101 
00102 private:
00103   const expr1_type                    m_expr1;
00104   const expr2_type                    m_expr2;
00105   const expr3_type                    m_expr3;
00106 };
00107 
00108 
00109 } // namespace tvmet
00110 
00111 #endif // TVMET_XPR_EVAL_H
00112 
00113 // Local Variables:
00114 // mode:C++
00115 // tab-width:8
00116 // End: