sprint/math/matrix_common.h

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/******************************************************************************
*   sprint::matrix_common
*
*   Copyright (C) 2004-2011  Paolo Medici <www.pmx.it>
*
*  This library is free software; you can redistribute it and/or
*  modify it under the terms of the GNU Lesser General Public
*  License as published by the Free Software Foundation; either
*  version 2.1 of the License, or (at your option) any later version.
*
*  This library is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
*  Lesser General Public License for more details.
*
*  You should have received a copy of the GNU Lesser General Public
*  License along with this library; if not, write to the Free Software
*  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*
*******************************************************************************/
#ifndef _MATRIX_COMMON_H
#define _MATRIX_COMMON_H

namespace sprint {

template<class T>
void transpose(T & dst, const T & src)
{
        for(unsigned int r =0; r <src.rows(); r++)
         for(unsigned int c =0; c <src.cols(); c++)
                        dst(c,r) = src(r,c);
}

template<typename A, typename B, typename C>
bool multiply(C & out, const A & a, const B & b)
  {
        unsigned int N = a.cols();
        typedef typename C::data_type T;
        if( 
          (N!=b.rows()) ||
        (out.rows()!=a.rows()) ||
          (out.cols()!=b.cols())
          )
                return false;

  for(unsigned int i=0;i<a.rows();i++)
    for(unsigned int j=0;j<b.cols();j++)
    {
    T sum = T(0);
    for(unsigned int k=0;k<N;k++)
      sum += a(i,k) * b(k,j);
    out(i,j) = sum;
    }

        return true;
  }
  
}

#endif