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muSpectre/tests/libmufft/test_fft_utils.cc
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test_fft_utils.cc
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/**
* @file test_fft_utils.cc
*
* @author Till Junge <till.junge@epfl.ch>
*
* @date 11 Dec 2017
*
* @brief test the small utility functions used by the fft engines and
* projections
*
* Copyright © 2017 Till Junge
*
* µSpectre 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 3, or (at
* your option) any later version.
*
* µSpectre 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 Lesser General Public License
* along with µSpectre; see the file COPYING. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* * Boston, MA 02111-1307, USA.
*
* Additional permission under GNU GPL version 3 section 7
*
* If you modify this Program, or any covered work, by linking or combining it
* with proprietary FFT implementations or numerical libraries, containing parts
* covered by the terms of those libraries' licenses, the licensors of this
* Program grant you additional permission to convey the resulting work.
*/
#include <boost/mpl/list.hpp>
#include "tests.hh"
#include <libmufft/fft_utils.hh>
namespace muFFT {
BOOST_AUTO_TEST_SUITE(fft_utils);
BOOST_AUTO_TEST_CASE(fft_freqs_test) {
// simply comparing to np.fft.fftfreq(12, 1/12.)
const std::valarray<Real> ref{0., 1., 2., 3., 4., 5.,
-6., -5., -4., -3., -2., -1.};
auto res{fft_freqs(12)};
Real error = std::abs(res - ref).sum();
BOOST_CHECK_EQUAL(error, 0.);
}
BOOST_AUTO_TEST_CASE(fft_freqs_test_length) {
// simply comparing to np.fft.fftfreq(10)
const std::valarray<Real> ref{0., 0.1, 0.2, 0.3, 0.4,
-0.5, -0.4, -0.3, -0.2, -0.1};
auto res{fft_freqs(10, 10.)};
Real error = std::abs(res - ref).sum();
BOOST_CHECK_EQUAL(error, 0.);
}
BOOST_AUTO_TEST_CASE(wave_vector_computation) {
// here, build a FFT_freqs and check it returns the correct xi's
constexpr Dim_t dim{twoD};
FFT_freqs<dim> freq_struc{{12, 10}, {1., 10.}};
Ccoord_t<dim> ccoord1{2, 3};
auto xi{freq_struc.get_xi(ccoord1)};
auto unit_xi{freq_struc.get_unit_xi(ccoord1)};
typename FFT_freqs<dim>::Vector ref;
ref << 2., .3; // from above tests
BOOST_CHECK_LT((xi - ref).norm(), tol);
BOOST_CHECK_LT(std::abs(xi.dot(unit_xi) - xi.norm()),
xi.norm() * tol);
BOOST_CHECK_LT(std::abs(unit_xi.norm() - 1.), tol);
ccoord1 = {7, 8};
xi = freq_struc.get_xi(ccoord1);
unit_xi = freq_struc.get_unit_xi(ccoord1);
ref << -5., -.2;
BOOST_CHECK_LT((xi - ref).norm(), tol);
BOOST_CHECK_LT(std::abs(xi.dot(unit_xi) - xi.norm()),
xi.norm() * tol);
BOOST_CHECK_LT(std::abs(unit_xi.norm() - 1.), tol);
}
BOOST_AUTO_TEST_SUITE_END();
} // namespace muFFT
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