anchor.diff:                         liblapack-dev \
                          libeigen3-dev \
                          libhdf5-dev \
  -                       hdf5-tools
  +                       hdf5-tools \
  +                       g++-8
   
   # need to put libhdf5.so on LD_LIBRARY_PATH
   ENV LD_LIBRARY_PATH /usr/lib/x86_64-linux-gnu
   
  -# switch to python 3
  +# switch to python 3 and to gcc8
   RUN update-alternatives --install /usr/bin/python python /usr/bin/python3 10; \
  -    update-alternatives --install /usr/bin/pip pip /usr/bin/pip3 10;
  +    update-alternatives --install /usr/bin/pip pip /usr/bin/pip3 10; \
  +    update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 7; \
  +    update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-7 7; \
  +    update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 8; \
  +    update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-8 8;
   
   # upgrade pip and install python dependencies
   ENV PATH $HOME/.local/bin:$PATH
  
positive.code: # build MOAB
  RUN mkdir moab \
      && cd moab \
      && git clone --branch Version5.1.0 --single-branch https://bitbucket.org/fathomteam/moab moab \
      && mkdir build \
      && cd build \
      && cmake ../moab/ \
  
negative.code:     && cd .. \
      && rm -rf build DAGMC
  
  
  # Install OpenMC API
  RUN git clone https://github.com/openmc-dev/openmc.git \
      && cd openmc && git checkout develop \
  