blitz Version 0.10
blitz/matsymm.h
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00001 // -*- C++ -*-
00002 /***************************************************************************
00003  * blitz/matsymm.h      Declarations for Symmetric matrices
00004  *
00005  * $Id: matsymm.h,v 1.5 2011/03/25 22:41:16 julianc Exp $
00006  *
00007  * Copyright (C) 1997-2011 Todd Veldhuizen <tveldhui@acm.org>
00008  *
00009  * This file is a part of Blitz.
00010  *
00011  * Blitz is free software: you can redistribute it and/or modify 
00012  * it under the terms of the GNU Lesser General Public License
00013  * as published by the Free Software Foundation, either version 3
00014  * of the License, or (at your option) any later version.
00015  *
00016  * Blitz is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public 
00022  * License along with Blitz.  If not, see <http://www.gnu.org/licenses/>.
00023  * 
00024  * Suggestions:          blitz-devel@lists.sourceforge.net
00025  * Bugs:                 blitz-support@lists.sourceforge.net    
00026  *
00027  * For more information, please see the Blitz++ Home Page:
00028  *    https://sourceforge.net/projects/blitz/
00029  *
00030  ***************************************************************************/
00031 
00032 #ifndef BZ_MATSYMM_H
00033 #define BZ_MATSYMM_H
00034 
00035 #ifndef BZ_MSTRUCT_H
00036  #error <blitz/matsymm.h> must be included via <blitz/mstruct.h>
00037 #endif
00038 
00039 BZ_NAMESPACE(blitz)
00040 
00041 // Symmetric, lower triangular row major ordering
00042 // [ 0 1 3 6 ]
00043 // [ 1 2 4 7 ]
00044 // [ 3 4 5 8 ]
00045 // [ 6 7 8 9 ]
00046 
00047 class SymmetricIterator {
00048 public:
00049     SymmetricIterator(unsigned rows, unsigned cols)
00050     {
00051         BZPRECONDITION(rows == cols);
00052         size_ = rows;
00053         good_ = true;
00054         offset_ = 0;
00055         i_ = 0;
00056         j_ = 0;
00057     }
00058    
00059     operator bool() const { return good_; }
00060 
00061     void operator++()
00062     {
00063         BZPRECONDITION(good_);
00064         ++offset_;
00065         ++j_;
00066         if (j_ > i_)
00067         {
00068             j_ = 0;
00069             ++i_;
00070             if (i_ == size_)
00071                 good_ = false;
00072         }
00073     }
00074 
00075     unsigned row() const
00076     { return i_; }
00077 
00078     unsigned col() const
00079     { return j_; }
00080 
00081     unsigned offset() const
00082     { return offset_; }
00083 
00084 protected:
00085     unsigned size_;
00086     bool     good_;
00087     unsigned offset_;
00088     unsigned i_, j_;
00089 };
00090 
00091 class Symmetric : public MatrixStructure {
00092 
00093 public:
00094     typedef SymmetricIterator T_iterator;
00095 
00096     Symmetric()
00097         : size_(0)
00098     { }
00099 
00100     Symmetric(unsigned size)
00101         : size_(size)
00102     { }
00103 
00104     Symmetric(unsigned rows, unsigned cols)
00105         : size_(rows)
00106     {
00107         BZPRECONDITION(rows == cols);
00108     }
00109 
00110     unsigned columns() const
00111     { return size_; }
00112 
00113     unsigned coordToOffset(unsigned i, unsigned j) const
00114     {
00115         BZPRECONDITION(inRange(i,j));
00116         if (i >= j)
00117             return i*(i+1)/2 + j;
00118         else
00119             return j*(j+1)/2 + i;
00120     }
00121 
00122     unsigned firstInRow(unsigned i) const
00123     { return 0; }
00124 
00125     template<typename T_numtype>
00126     T_numtype get(const T_numtype * restrict data,
00127         unsigned i, unsigned j) const
00128     {
00129         BZPRECONDITION(inRange(i,j));
00130         return data[coordToOffset(i,j)];
00131     }
00132 
00133     template<typename T_numtype>
00134     T_numtype& get(T_numtype * restrict data, unsigned i, unsigned j)
00135     {
00136         BZPRECONDITION(inRange(i,j));
00137         return data[coordToOffset(i,j)];
00138     }
00139 
00140     unsigned lastInRow(unsigned i) const
00141     { return i; }
00142 
00143     unsigned firstInCol(unsigned j) const
00144     { return j; }
00145 
00146     unsigned lastInCol(unsigned j) const
00147     { return size_ - 1; }
00148 
00149     bool inRange(unsigned i, unsigned j) const {
00150         return (i < size_) && (j < size_);
00151     }
00152 
00153     unsigned numElements() const
00154     { return size_ * (size_ + 1) / 2; }
00155 
00156     unsigned rows() const
00157     { return size_; }
00158 
00159     void resize(unsigned size)
00160     {
00161         size_ = size;
00162     }
00163 
00164     void resize(unsigned rows, unsigned cols)
00165     {
00166         BZPRECONDITION(rows == cols);
00167         size_  = rows;
00168     }
00169 
00170 private:
00171     unsigned size_;
00172 };
00173 
00174 BZ_NAMESPACE_END
00175 
00176 #endif // BZ_MATSYMM_H
00177 
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