Identity.h

00001 /*
00002  * $Id: Identity.h,v 1.4 2006-11-21 18:43:09 opetzold Exp $
00003  */
00004 
00005 #ifndef TVMET_XPR_IDENTITY_H
00006 #define TVMET_XPR_IDENTITY_H
00007 
00008 
00009 namespace tvmet {
00010 
00011 
00012 /**
00013  * \class XprIdentity Identity.h "tvmet/xpr/Identity.h"
00014  * \brief Expression for the identity matrix.
00015  *
00016  * This expression doesn't hold any other expression, it
00017  * simply returns 1 or 0 depends where the row and column
00018  * element excess is done.
00019  *
00020  * \since release 1.6.0
00021  * \sa identity
00022  */
00023 template<class T, std::size_t Rows, std::size_t Cols>
00024 struct XprIdentity
00025   : public TvmetBase< XprIdentity<T, Rows, Cols> >
00026 {
00027   XprIdentity& operator=(const XprIdentity&);
00028 
00029 public:
00030   typedef T             value_type;
00031 
00032 public:
00033   /** Complexity counter. */
00034   enum {
00035     ops_assign = Rows * Cols,
00036     ops        = ops_assign
00037   };
00038 
00039 public:
00040   /** access by index. */
00041   value_type operator()(std::size_t i, std::size_t j) const {
00042     return i==j ? 1 : 0;
00043   }
00044 
00045 public: // debugging Xpr parse tree
00046   void print_xpr(std::ostream& os, std::size_t l=0) const {
00047     os << IndentLevel(l++)
00048        << "XprIdentity[O="<< ops << ")]<"
00049        << std::endl;
00050     os << IndentLevel(l)
00051        << typeid(T).name() << ","
00052        << "R=" << Rows << ", C=" << Cols << std::endl;
00053     os << IndentLevel(--l) << ">"
00054        << ((l != 0) ? "," : "") << std::endl;
00055   }
00056 };
00057 
00058 
00059 } // namespace tvmet
00060 
00061 
00062 #endif // TVMET_XPR_IDENTITY_H
00063 
00064 
00065 // Local Variables:
00066 // mode:C++
00067 // tab-width:8
00068 // End: