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120 lines
4.1 KiB
C++
120 lines
4.1 KiB
C++
/*************************************************************************************
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Grid physics library, www.github.com/paboyle/Grid
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Source file: ./tests/Test_remez.cc
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Copyright (C) 2015
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Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>
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Author: Peter Boyle <paboyle@ph.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/Grid.h>
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using namespace std;
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using namespace Grid;
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using namespace Grid::QCD;
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int main (int argc, char ** argv)
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{
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Grid_init(&argc,&argv);
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std::cout<<GridLogMessage << "Testing Remez"<<std::endl;
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double lo=1.0e-3;
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double hi=5.0;
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int precision=64;
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int degree=16;
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AlgRemez remez(lo,hi,precision);
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////////////////////////////////////////
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// sqrt and inverse sqrt
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////////////////////////////////////////
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std::cout<<GridLogMessage << "Generating degree "<<degree<<" for x^(1/2)"<<std::endl;
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remez.generateApprox(degree,1,2);
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MultiShiftFunction Root2(remez,1.0,false);
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MultiShiftFunction InvRoot2(remez,1.0,true);
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std::cout<<GridLogMessage << "Generating degree "<<degree<<" for x^(1/4)"<<std::endl;
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remez.generateApprox(degree,1,4);
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MultiShiftFunction Root4(remez,1.0,false);
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MultiShiftFunction InvRoot4(remez,1.0,true);
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std::cout<<GridLogMessage << "Generating degree "<<degree<<" for x^(1/8)"<<std::endl;
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remez.generateApprox(degree,1,8);
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MultiShiftFunction Root8(remez,1.0,false);
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MultiShiftFunction InvRoot8(remez,1.0,true);
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std::cout<<GridLogMessage << "Generating degree "<<degree<<" for x^(1/16)"<<std::endl;
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remez.generateApprox(degree,1,16);
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MultiShiftFunction Root16(remez,1.0,false);
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MultiShiftFunction InvRoot16(remez,1.0,true);
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std::cout<<GridLogMessage << "Generating degree "<<degree<<" for x^(1/32)"<<std::endl;
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remez.generateApprox(degree,1,32);
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MultiShiftFunction Root32(remez,1.0,false);
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MultiShiftFunction InvRoot32(remez,1.0,true);
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ofstream gnuplot(std::string("Root2.gnu"),std::ios::out|std::ios::trunc);
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Root2.gnuplot(gnuplot);
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ofstream gnuplot_i2(std::string("InvRoot2.gnu"),std::ios::out|std::ios::trunc);
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InvRoot2.gnuplot(gnuplot_i2);
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ofstream gnuplot_i4(std::string("InvRoot4.gnu"),std::ios::out|std::ios::trunc);
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InvRoot4.gnuplot(gnuplot_i4);
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ofstream gnuplot_i8(std::string("InvRoot8.gnu"),std::ios::out|std::ios::trunc);
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InvRoot8.gnuplot(gnuplot_i8);
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ofstream gnuplot_i16(std::string("InvRoot16.gnu"),std::ios::out|std::ios::trunc);
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InvRoot16.gnuplot(gnuplot_i16);
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ofstream gnuplot_i32(std::string("InvRoot32.gnu"),std::ios::out|std::ios::trunc);
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InvRoot32.gnuplot(gnuplot_i32);
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double x=0.6789;
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double sx=std::sqrt(x);
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double ssx=std::sqrt(sx);
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double isx=1.0/sx;
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double issx=1.0/ssx;
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double asx =Root2.approx(x);
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double assx =Root4.approx(x);
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double aisx =InvRoot2.approx(x);
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double aissx=InvRoot4.approx(x);
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std::cout<<GridLogMessage << "x^(1/2) : "<<sx<<" "<<asx<<std::endl;
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std::cout<<GridLogMessage << "x^(1/4) : "<<ssx<<" "<<assx<<std::endl;
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std::cout<<GridLogMessage << "x^(-1/2): "<<isx<<" "<<aisx<<std::endl;
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std::cout<<GridLogMessage << "x^(-1/4): "<<issx<<" "<<aissx<<std::endl;
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assert(fabs(sx-asx)<1.0e-6);
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assert(fabs(ssx-assx)<1.0e-6);
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assert(fabs(isx-aisx)<1.0e-6);
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assert(fabs(issx-aissx)<1.0e-6);
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Grid_finalize();
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}
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