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dft_tools/test/triqs/arrays/tridiag.cpp
Olivier Parcollet 9265c2db7f Fix #119
- Cleaned of the eigensystems computations (worker is simpler, decision
  at runtime, etc..).
- Fix #119 : When the matrix is in C order, the fortran lapack
  sees in fact its conjugate, so we need to conjugate the eigenvectors at the end.
  NB : not true if the storage order of the matrix is already fortran of course.
2014-09-04 11:55:32 +02:00

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1.9 KiB
C++

/*******************************************************************************
*
* TRIQS: a Toolbox for Research in Interacting Quantum Systems
*
* Copyright (C) 2011 by O. Parcollet
*
* TRIQS 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 3 of the License, or (at your option) any later
* version.
*
* TRIQS 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
* TRIQS. If not, see <http://www.gnu.org/licenses/>.
*
******************************************************************************/
#include "./common.hpp"
#include <triqs/arrays/linalg/eigenelements.hpp>
#include <triqs/arrays/blas_lapack/stev.hpp>
using namespace triqs::arrays;
using namespace triqs;
int main(int argc, char **argv) {
arrays::vector<double> D (5), DD(4);
for (size_t i=0; i<5; ++i) {D(i) = 3.2*i+2.3;}
for (size_t i=0; i<4; ++i) {DD(i) = 2.4*(i+1.82) + 0.78;}
auto R = range(0,5);
blas::tridiag_worker w(10);
w(D,DD);
std::cerr<<" values = "<< w.values()<<std::endl;
std::cerr<<" vectors = "<< w.vectors()(R,R)<<std::endl;
//check
matrix<double> A(5,5); A()=0;
for (size_t i=0; i<5; ++i) A(i,i) = D(i);
for (size_t i=0; i<4; ++i) { A(i,i+1) = DD(i); A(i+1,i) = DD(i);}
std::cerr<<"A = "<<A<<std::endl;
auto eig = linalg::eigenelements(A());
std::cerr<<" check values = "<< eig.first<<std::endl;
std::cerr<<" check vectors = "<< eig.second<<std::endl;
assert_all_close(w.vectors()(R,R), eig.second, 1.e-10);
assert_all_close(array_view<double,1>(w.values()), eig.first, 1.e-10);
return 0;
}