Page MenuHomec4science
Files F65894670

statistics.cpp
No OneTemporary
Actions

File Metadata

Created
Thu, Jun 6, 22:34

statistics.cpp
View Options

/**
* @file
*
* @author Guillaume Anciaux <guillaume.anciaux@epfl.ch>
* @author Lucas Frérot <lucas.frerot@epfl.ch>
*
* @section LICENSE
*
* Copyright (©) 2016-2017 EPFL (Ecole Polytechnique Fédérale de
* Lausanne) Laboratory (LSMS - Laboratoire de Simulation en Mécanique des
* Solides)
*
* Tamaas 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 of the License, or (at your option) any
* later version.
*
* Tamaas 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 Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Tamaas. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "statistics.hh"
#include "loop.hh"
#include "static_types.hh"
/* -------------------------------------------------------------------------- */
__BEGIN_TAMAAS__
template <UInt dim>
Real Statistics<dim>::computeSpectralRMSSlope(Grid<Real, dim>& surface) {
auto h_size = GridHermitian<Real, dim>::hermitianDimensions(surface.sizes());
auto wavevectors =
FFTransform<Real, dim>::template computeFrequencies<true>(h_size);
auto psd = computePowerSpectrum(surface);
auto end = wavevectors.end(dim);
Real rms_slope_mean = 0;
rms_slope_mean = Loop::stridedReduce<operation::plus>(
[] CUDA_LAMBDA(StaticVector<Real, dim> && q, Complex & psd_val) {
return q.l2squared() * psd_val.real();
},
wavevectors, psd);
rms_slope_mean /= wavevectors.getNbPoints(); // average
rms_slope_mean *= 2; // because we have a hermitian surface
return rms_slope_mean;
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
GridHermitian<Real, dim>
Statistics<dim>::computePowerSpectrum(Grid<Real, dim>& surface) {
auto h_size = GridHermitian<Real, dim>::hermitianDimensions(surface.sizes());
GridHermitian<Real, dim> psd(h_size, surface.getNbComponents());
FFTPlanManager::get().createPlan(surface, psd).forwardTransform();
Real factor = surface.getNbPoints();
factor = 1. / (factor * factor);
// Squaring the fourier transform of surface and normalizing
Loop::loop(
[factor] CUDA_LAMBDA(Complex & c) {
c *= conj(c);
c *= factor;
},
psd);
FFTPlanManager::get().destroyPlan(surface, psd);
return psd;
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
Grid<Real, dim>
Statistics<dim>::computeAutocorrelation(Grid<Real, dim>& surface) {
Grid<Real, dim> acf(surface.sizes(), surface.getNbComponents());
auto psd = computePowerSpectrum(surface);
FFTPlanManager::get().createPlan(acf, psd).backwardTransform();
acf *= acf.getNbPoints();
FFTPlanManager::get().destroyPlan(acf, psd);
return acf;
}
/* -------------------------------------------------------------------------- */
namespace {
template <UInt dim>
class moment_helper {
public:
moment_helper(const std::array<UInt, dim>& exp) : exponent(exp) {}
CUDA_LAMBDA Complex operator()(const StaticVector<const Real, dim>& q,
const Complex& phi) const {
Real mul = 1;
for (UInt i = 0; i < dim; ++i)
mul *= std::pow(q(i), exponent[i]);
return mul * phi;
}
private:
std::array<UInt, dim> exponent;
};
}
template <>
std::vector<Real> Statistics<1>::computeMoments(Grid<Real, 1>& surface) {
constexpr UInt dim = 1;
std::vector<Real> moments(3);
const auto psd = computePowerSpectrum(surface);
const auto wavevectors =
FFTransform<Real, dim>::template computeFrequencies<true>(psd.sizes());
moments[0] = psd.sum().real();
moments[1] =
Loop::reduce<operation::plus>(moment_helper<dim>{{{2}}}, wavevectors, psd)
.real();
moments[2] =
Loop::reduce<operation::plus>(moment_helper<dim>{{{4}}}, wavevectors, psd)
.real();
return moments;
}
template <>
std::vector<Real> Statistics<2>::computeMoments(Grid<Real, 2>& surface) {
constexpr UInt dim = 2;
std::vector<Real> moments(3);
const auto psd = computePowerSpectrum(surface);
const auto wavevectors =
FFTransform<Real, dim>::template computeFrequencies<true>(psd.sizes());
moments[0] = psd.sum().real();
auto m02 = Loop::reduce<operation::plus>(moment_helper<dim>{{{0, 2}}},
wavevectors, psd)
.real();
auto m20 = Loop::reduce<operation::plus>(moment_helper<dim>{{{2, 0}}},
wavevectors, psd)
.real();
moments[1] = 0.5 * (m02 + m20);
auto m22 = Loop::reduce<operation::plus>(moment_helper<dim>{{{2, 2}}},
wavevectors, psd)
.real();
auto m40 = Loop::reduce<operation::plus>(moment_helper<dim>{{{4, 0}}},
wavevectors, psd)
.real();
auto m04 = Loop::reduce<operation::plus>(moment_helper<dim>{{{0, 4}}},
wavevectors, psd)
.real();
moments[2] = (3 * m22 + m40 + m04) / 3.;
return moments;
}
template struct Statistics<1>;
template struct Statistics<2>;
__END_TAMAAS__

Event Timeline

c4science · Help