diff --git a/src/core/fft_engine.hh b/src/core/fft_engine.hh
index 09791fc..8484618 100644
--- a/src/core/fft_engine.hh
+++ b/src/core/fft_engine.hh
@@ -1,151 +1,154 @@
/**
* @file
* @section LICENSE
*
* Copyright (©) 2016-2020 EPFL (École Polytechnique Fédérale de Lausanne),
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*
*/
/* -------------------------------------------------------------------------- */
#ifndef FFT_ENGINE_H
#define FFT_ENGINE_H
/* -------------------------------------------------------------------------- */
#include "fftw_interface.hh"
#include "grid.hh"
#include "grid_base.hh"
#include "grid_hermitian.hh"
#include
#include