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Grid/lib/algorithms/iterative/EigenSort.h

80 lines
2.4 KiB
C++

/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/algorithms/iterative/EigenSort.h
Copyright (C) 2015
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/* END LEGAL */
#ifndef GRID_EIGENSORT_H
#define GRID_EIGENSORT_H
namespace Grid {
/////////////////////////////////////////////////////////////
// Eigen sorter to begin with
/////////////////////////////////////////////////////////////
template<class Field>
class SortEigen {
private:
static bool less_lmd(RealD left,RealD right){
return fabs(left) < fabs(right);
}
static bool less_pair(std::pair<RealD,Field>& left,
std::pair<RealD,Field>& right){
return fabs(left.first) < fabs(right.first);
}
public:
void push(DenseVector<RealD>& lmd,
DenseVector<Field>& evec,int N) {
DenseVector<std::pair<RealD, Field> > emod;
typename DenseVector<std::pair<RealD, Field> >::iterator it;
for(int i=0;i<lmd.size();++i){
emod.push_back(std::pair<RealD,Field>(lmd[i],evec[i]));
}
partial_sort(emod.begin(),emod.begin()+N,emod.end(),less_pair);
it=emod.begin();
for(int i=0;i<N;++i){
lmd[i]=it->first;
evec[i]=it->second;
++it;
}
}
void push(DenseVector<RealD>& lmd,int N) {
std::partial_sort(lmd.begin(),lmd.begin()+N,lmd.end(),less_lmd);
}
bool saturated(RealD lmd, RealD thrs) {
return fabs(lmd) > fabs(thrs);
}
};
}
#endif