anchor.diff:      cd build && \
       cmake -DUSE_VTK=ON \
             -DUSE_SYSTEM_VTK=ON \
  +          -DVTK_DIR=$HOME/vtk/build \
             ../ANTs && \
       make -j $N_CPUS && \
       make install && \
  
positive.code: #-------------------------------------------------------------------------------
  # ANTS (https://github.com/stnava/ANTs)
  #-------------------------------------------------------------------------------
  RUN apt-get -y install libvtk6-dev
  
  RUN \
      mkdir ants && \
      cd ants && \
  
negative.code: 
  ENV PETPVC_VERSION master
  ENV ITK_VERSION v4.10.0
  ENV VTK_VERSION v6.3.0
  ENV SIMPLEITK_VERSION v0.10.0
  ENV ANTS_VERSION v2.1.0
  ENV N_CPUS 2
  