diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d71118..7f59663 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,117 +1,119 @@
 # =============================================================================
 # file   CMakeLists.txt
 #
 # @author Till Junge <till.junge@epfl.ch>
 #
 # @date   08 Jan 2018
 #
 # @brief  Main configuration file
 #
 # @section LICENCE
 #
 # Copyright © 2018 Till Junge
 #
 # µSpectre 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, 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 General Public License
 # along with GNU Emacs; see the file COPYING. If not, write to the
 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 # Boston, MA 02111-1307, USA.
 # =============================================================================
 
 cmake_minimum_required(VERSION 3.7.0)
 project(µSpectre)
 
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 set(BUILD_SHARED_LIBS ON)
 
 add_compile_options(-Wall -Wextra -Weffc++)
 
 
 enable_testing()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake)
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
   # using Clang
   add_compile_options(-Wno-missing-braces)
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
   # using GCC
   string( TOLOWER "${CMAKE_BUILD_TYPE}" build_type )
   if ("release" STREQUAL "${build_type}" )
     add_compile_options(-march=native)
   endif()
   if ("debug" STREQUAL "${build_type}" )
     add_compile_options(-O0)
   endif()
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
   # using Intel C++
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
   # using Visual Studio C++
 endif()
 
 find_package(Boost COMPONENTS unit_test_framework REQUIRED)
 find_package(Eigen3 3.3 REQUIRED NO_MODULE)
 
 include_directories(
   tests
   src
   ${EIGEN3_INCLUDE_DIRS}
+  ${Boost_INCLUDE_DIRS}
+  ${FFTW_INCLUDES}
   )
 
 #find_package(MPI REQUIRED)
 find_package(FFTW REQUIRED)
 #find_package(FFTWMPI REQUIRED)
 
 
 #build tests
 file( GLOB TEST_SRCS "${CMAKE_SOURCE_DIR}/tests/test_*.cc")
 
 add_executable(main_test_suite tests/main_test_suite.cc ${TEST_SRCS})
 target_link_libraries(main_test_suite ${Boost_LIBRARIES} muSpectre)
 add_test(main_test_suite main_test_suite --report_level=detailed --build_info=TRUE)
 #add_test(main_test_suite main_test_suite --build_info=TRUE)
 
 
 
 # compile the library
 add_compile_options( -Werror)
 add_subdirectory(
   "${CMAKE_SOURCE_DIR}/src/"
   )
 
 
 #compile executables
 file( GLOB binaries "${CMAKE_SOURCE_DIR}/bin/*.cc")
 foreach(binaryfile ${binaries})
   get_filename_component(binaryname  ${binaryfile} NAME_WE)
   add_executable(${binaryname} ${binaryfile})
   target_link_libraries(${binaryname} ${Boost_LIBRARIES} muSpectre)
 endforeach(binaryfile ${binaries})
 
 
 # compile benchmarks
 
 file(GLOB benchmarks "${CMAKE_SOURCE_DIR}/benchmarks/benchmark*cc")
 foreach(benchmark ${benchmarks})
   get_filename_component(benchmark_name ${benchmark} NAME_WE)
   add_executable(${benchmark_name} ${benchmark})
   target_link_libraries(${benchmark_name} ${BOOST_LIBRARIES} muSpectre)
 endforeach(benchmark ${benchmark})
 
 
 # copy python test
 configure_file(
   "${CMAKE_SOURCE_DIR}/tests/python_binding_tests.py"
   "${CMAKE_BINARY_DIR}/python_binding_tests.py"
   COPYONLY)
 add_test(python_binding_test python_binding_tests.py)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 12ffbe4..0c8568a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,50 +1,66 @@
 # =============================================================================
 # file   CMakeLists.txt
 #
 # @author Till Junge <till.junge@epfl.ch>
 #
 # @date   08 Jan 2018
 #
 # @brief  Configuration for libmuSpectre
 #
 # @section LICENCE
 #
 # Copyright © 2018 Till Junge
 #
 # µSpectre 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, 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 General Public License
 # along with GNU Emacs; see the file COPYING. If not, write to the
 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 # Boston, MA 02111-1307, USA.
 # =============================================================================
 
 include_directories(
   common
   materials
   system
   external
   )
 
 set (muSpectre_SRC
   )
 add_subdirectory(common)
 add_subdirectory(materials)
 add_subdirectory(fft)
 add_subdirectory(system)
 add_subdirectory(solver)
 
 find_package(FFTW REQUIRED)
 
+
+# The following checks whether std::optional exists and replaces it by
+# boost::optional if necessary
+include(CheckCXXSourceCompiles)
+CHECK_CXX_SOURCE_COMPILES(
+    "#include <experimental/optional>
+int main() {
+std::experimental::optional<double> A{};
+}"
+    HAS_STD_OPTIONAL)
+
+if( NOT HAS_STD_OPTIONAL)
+  add_definitions(-DNO_EXPERIMENTAL)
+endif()
+
+
 add_library(muSpectre ${muSpectre_SRC})
 target_link_libraries(muSpectre Eigen3::Eigen ${FFTW_LIBRARIES})
 
 add_subdirectory(language_bindings)
diff --git a/src/common/utilities.hh b/src/common/utilities.hh
index fa2b43b..174af67 100644
--- a/src/common/utilities.hh
+++ b/src/common/utilities.hh
@@ -1,172 +1,200 @@
 /**
  * file   utilities.hh
  *
  * @author Till Junge <till.junge@epfl.ch>
  *
  * @date   17 Nov 2017
  *
  * @brief  additions to the standard name space to anticipate C++17 features
  *
  * @section LICENCE
  *
  * Copyright © 2017 Till Junge
  *
  * µSpectre 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, 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 General Public License
  * along with GNU Emacs; see the file COPYING. If not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
 
 
 #ifndef UTILITIES_H
 #define UTILITIES_H
 
 #include <boost/tuple/tuple.hpp>
 
 #include <tuple>
-#include <experimental/optional>
+
+#ifdef NO_EXPERIMENTAL
+#  if defined(__INTEL_COMPILER)
+//#    pragma warning ( disable : 383 )
+#  elif defined (__clang__) // test clang to be sure that when we test for gnu it is only gnu
+#    pragma clang diagnostic push
+#    pragma clang diagnostic ignored "Weffc++"
+#  elif (defined(__GNUC__) || defined(__GNUG__))
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Weffc++"
+#  endif
+#  include <boost/optional.hpp>
+#  if defined(__INTEL_COMPILER)
+//#    pragma warning ( disable : 383 )
+#  elif defined (__clang__) // test clang to be sure that when we test for gnu it is only gnu
+#    pragma clang diagnostic pop
+#    pragma clang diagnostic ignored "Weffc++"
+#  elif (defined(__GNUC__) || defined(__GNUG__))
+#    pragma GCC diagnostic pop
+#    pragma GCC diagnostic ignored "-Weffc++"
+#  endif
+#else
+#  include <experimental/optional>
+#endif
 
 namespace std_replacement {
 
   namespace detail {
     template <class T>
     struct is_reference_wrapper : std::false_type {};
     template <class U>
     struct is_reference_wrapper<std::reference_wrapper<U>> : std::true_type {};
     template <class T>
     constexpr bool is_reference_wrapper_v = is_reference_wrapper<T>::value;
 
     template <class Base, class T, class Derived, class... Args>
     auto INVOKE(T Base::*pmf, Derived&& ref, Args&&... args)
       noexcept(noexcept((std::forward<Derived>(ref).*pmf)(std::forward<Args>(args)...)))
       -> std::enable_if_t<std::is_function<T>::value &&
                           std::is_base_of<Base, std::decay_t<Derived>>::value,
                           decltype((std::forward<Derived>(ref).*pmf)(std::forward<Args>(args)...))>
     {
       return (std::forward<Derived>(ref).*pmf)(std::forward<Args>(args)...);
     }
 
     template <class Base, class T, class RefWrap, class... Args>
     auto INVOKE(T Base::*pmf, RefWrap&& ref, Args&&... args)
       noexcept(noexcept((ref.get().*pmf)(std::forward<Args>(args)...)))
       -> std::enable_if_t<std::is_function<T>::value &&
                           is_reference_wrapper_v<std::decay_t<RefWrap>>,
                           decltype((ref.get().*pmf)(std::forward<Args>(args)...))>
 
     {
       return (ref.get().*pmf)(std::forward<Args>(args)...);
     }
 
     template <class Base, class T, class Pointer, class... Args>
     auto INVOKE(T Base::*pmf, Pointer&& ptr, Args&&... args)
       noexcept(noexcept(((*std::forward<Pointer>(ptr)).*pmf)(std::forward<Args>(args)...)))
       -> std::enable_if_t<std::is_function<T>::value &&
                           !is_reference_wrapper_v<std::decay_t<Pointer>> &&
                           !std::is_base_of<Base, std::decay_t<Pointer>>::value,
                           decltype(((*std::forward<Pointer>(ptr)).*pmf)(std::forward<Args>(args)...))>
     {
       return ((*std::forward<Pointer>(ptr)).*pmf)(std::forward<Args>(args)...);
     }
 
     template <class Base, class T, class Derived>
     auto INVOKE(T Base::*pmd, Derived&& ref)
       noexcept(noexcept(std::forward<Derived>(ref).*pmd))
       -> std::enable_if_t<!std::is_function<T>::value &&
                           std::is_base_of<Base, std::decay_t<Derived>>::value,
                           decltype(std::forward<Derived>(ref).*pmd)>
     {
       return std::forward<Derived>(ref).*pmd;
     }
 
     template <class Base, class T, class RefWrap>
     auto INVOKE(T Base::*pmd, RefWrap&& ref)
       noexcept(noexcept(ref.get().*pmd))
       -> std::enable_if_t<!std::is_function<T>::value &&
                           is_reference_wrapper_v<std::decay_t<RefWrap>>,
                           decltype(ref.get().*pmd)>
     {
       return ref.get().*pmd;
     }
 
     template <class Base, class T, class Pointer>
     auto INVOKE(T Base::*pmd, Pointer&& ptr)
       noexcept(noexcept((*std::forward<Pointer>(ptr)).*pmd))
       -> std::enable_if_t<!std::is_function<T>::value &&
                           !is_reference_wrapper_v<std::decay_t<Pointer>> &&
                           !std::is_base_of<Base, std::decay_t<Pointer>>::value,
                           decltype((*std::forward<Pointer>(ptr)).*pmd)>
     {
       return (*std::forward<Pointer>(ptr)).*pmd;
     }
 
     template <class F, class... Args>
     auto INVOKE(F&& f, Args&&... args)
       noexcept(noexcept(std::forward<F>(f)(std::forward<Args>(args)...)))
       -> std::enable_if_t<!std::is_member_pointer<std::decay_t<F>>::value,
                           decltype(std::forward<F>(f)(std::forward<Args>(args)...))>
     {
       return std::forward<F>(f)(std::forward<Args>(args)...);
     }
   } // namespace detail
 
   template< class F, class... ArgTypes >
   auto invoke(F&& f, ArgTypes&&... args)
   // exception specification for QoI
     noexcept(noexcept(detail::INVOKE(std::forward<F>(f), std::forward<ArgTypes>(args)...)))
     -> decltype(detail::INVOKE(std::forward<F>(f), std::forward<ArgTypes>(args)...))
   {
     return detail::INVOKE(std::forward<F>(f), std::forward<ArgTypes>(args)...);
   }
 
   namespace detail {
     template <class F, class Tuple, std::size_t... I>
     constexpr decltype(auto) apply_impl(F &&f, Tuple &&t, std::index_sequence<I...>)
     {
       return std_replacement::invoke(std::forward<F>(f), std::get<I>(std::forward<Tuple>(t))...);
     }
   }  // namespace detail
 
   template <class F, class Tuple>
   constexpr decltype(auto) apply(F &&f, Tuple &&t)
   {
     return detail::apply_impl
       (std::forward<F>(f), std::forward<Tuple>(t),
        std::make_index_sequence<std::tuple_size<std::decay_t<Tuple>>::value>{});
   }
 
 
 } //namespace std_replacement
 
+
 namespace muSpectre {
 
   using std_replacement::apply;
 
   template <class T>
+#ifdef NO_EXPERIMENTAL
+  using optional = typename boost::optional<T>;
+#else
   using optional = typename std::experimental::optional<T>;
+#endif
 
   /* ---------------------------------------------------------------------- */
   template <typename BoostTuple, std::size_t... Is>
   auto asStdTuple(BoostTuple&& boostTuple, std::index_sequence<Is...>) {
     return std::tuple<typename boost::tuples::element<Is, std::decay_t<BoostTuple>>::type...>
       (boost::get<Is>(std::forward<BoostTuple>(boostTuple))...);
   }
   template <typename BoostTuple>
   auto asStdTuple(BoostTuple&& boostTuple) {
     return asStdTuple(std::forward<BoostTuple>(boostTuple),
                       std::make_index_sequence<boost::tuples::length<std::decay_t<BoostTuple>>::value>());
   }
 
 
 }  // muSpectre
 
 #endif /* UTILITIES_H */
diff --git a/tests/test_fft_utils.cc b/tests/test_fft_utils.cc
index 3030e71..7c3e678 100644
--- a/tests/test_fft_utils.cc
+++ b/tests/test_fft_utils.cc
@@ -1,83 +1,82 @@
 /**
  * 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
  *
  * @section LICENCE
  *
  * Copyright © 2017 Till Junge
  *
  * µSpectre 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, 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 General Public License
  * along with GNU Emacs; see the file COPYING. If not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
 #include <boost/mpl/list.hpp>
-#include "boost/range/combine.hpp"
 
 #include "tests.hh"
 #include "fft/fft_utils.hh"
 
 namespace muSpectre {
 
   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 = 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 = 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(abs(xi.dot(unit_xi)-xi.norm()), xi.norm()*tol);
     BOOST_CHECK_LT(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(abs(xi.dot(unit_xi)-xi.norm()), xi.norm()*tol);
     BOOST_CHECK_LT(abs(unit_xi.norm()-1.), tol);
   }
 
   BOOST_AUTO_TEST_SUITE_END();
 
 }  // muSpectre
diff --git a/tests/tests.hh b/tests/tests.hh
index c37f3ce..0666ccd 100644
--- a/tests/tests.hh
+++ b/tests/tests.hh
@@ -1,45 +1,63 @@
 /**
  * file   tests.hh
  *
  * @author Till Junge <till.junge@epfl.ch>
  *
  * @date   10 May 2017
  *
  * @brief  common defs for tests
  *
  * @section LICENCE
  *
  * Copyright © 2017 Till Junge
  *
  * µSpectre 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, 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 General Public License
  * along with GNU Emacs; see the file COPYING. If not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
 
 #include "common/common.hh"
+#  if defined(__INTEL_COMPILER)
+//#    pragma warning ( disable : 383 )
+#  elif defined (__clang__) // test clang to be sure that when we test for gnu it is only gnu
+#    pragma clang diagnostic push
+#    pragma clang diagnostic ignored "Weffc++"
+#  elif (defined(__GNUC__) || defined(__GNUG__))
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Weffc++"
+#  endif
 #include <boost/test/unit_test.hpp>
 #include <boost/mpl/list.hpp>
+#  if defined(__INTEL_COMPILER)
+//#    pragma warning ( disable : 383 )
+#  elif defined (__clang__) // test clang to be sure that when we test for gnu it is only gnu
+#    pragma clang diagnostic pop
+#    pragma clang diagnostic ignored "Weffc++"
+#  elif (defined(__GNUC__) || defined(__GNUG__))
+#    pragma GCC diagnostic pop
+#    pragma GCC diagnostic ignored "-Weffc++"
+#  endif
 
 #ifndef TESTS_H
 #define TESTS_H
 
 namespace muSpectre {
 
 
   const Real tol = 1e-14*100; //it's in percent
 
 }  // muSpectre
 
 
 #endif /* TESTS_H */