anchor.diff:      python
       cudatoolkit
       nvidia_x11
  +    gtest
     ]; 
   
     meta = with stdenv.lib; {
  
positive.code: , python
  , cudatoolkit
  , nvidia_x11
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:     cmake ../src -DCMAKE_INSTALL_PREFIX=$out \
                   -DCMAKE_BUILD_TYPE=Release \
                   -DOPENCL_ROOT=${cudatoolkit} \
                   -DUSE_SYSTEM_GTEST=ON
    '';
  
    dontStrip = true; 
  