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57 lines
1.8 KiB
C++
57 lines
1.8 KiB
C++
/*************************************************************************************
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Grid physics library, www.github.com/paboyle/Grid
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Source file: ./lib/algorithms/approx/MultiShiftFunction.cc
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Copyright (C) 2015
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Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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See the full license in the file "LICENSE" in the top level distribution directory
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*************************************************************************************/
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/* END LEGAL */
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#include <Grid/GridCore.h>
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namespace Grid {
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double MultiShiftFunction::approx(double x)
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{
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double a = norm;
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for(int n=0;n<poles.size();n++){
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a = a + residues[n]/(x+poles[n]);
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}
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return a;
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}
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void MultiShiftFunction::gnuplot(std::ostream &out)
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{
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out<<"f(x) = "<<norm<<"";
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for(int n=0;n<poles.size();n++){
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out<<"+("<<residues[n]<<"/(x+"<<poles[n]<<"))";
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}
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out<<";"<<std::endl;
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}
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void MultiShiftFunction::csv(std::ostream &out)
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{
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for (double x=lo; x<hi; x*=1.05) {
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double f = approx(x);
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double r = sqrt(x);
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out<< x<<","<<r<<","<<f<<","<<r-f<<std::endl;
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}
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return;
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}
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}
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