anchor.diff:  #-------------------------------------------------------------------------------
   # ANTS (https://github.com/stnava/ANTs)
   #-------------------------------------------------------------------------------
  -RUN apt-get -y install libvtk6-dev
  -
   RUN \
       mkdir ants && \
       cd ants && \
  
positive.code: 
  ENV PETPVC_VERSION master
  ENV ITK_VERSION v4.10.0
  ENV VTK_VERSION v7.0.0
  ENV SIMPLEITK_VERSION v0.10.0
  ENV ANTS_VERSION v2.1.0
  ENV N_CPUS 2
  
negative.code:     cd build && \
      cmake -DUSE_VTK=ON \
            -DUSE_SYSTEM_VTK=ON \
            -DVTK_DIR=$HOME/vtk/build \
            ../ANTs && \
      make -j $N_CPUS && \
      make install && \
  