anchor.diff:  } :
   
   assert builtins.elem network [ "ethernet" "infiniband" "omnipath" ];
  -
  -assert
  -  (if network == "infiniband"
  -     then (lib.lists.all (x: x != null) [ infiniband-diags opensm rdma-core ])
  -     else true
  -  );
  -
  -assert
  -  (if network == "omnipath"
  -     then (lib.lists.all (x: x != null) [ libpsm2 libfabric ])
  -     else true
  -  );
   
   let
   
  
positive.code:     "--enable-threads=multiple"
      "--enable-hybrid"
      "--enable-shared"
    ] ++ lib.optionals useSlurm [ "--with-pmi=pmi1" "--with-pm=slurm" ]
      ++ lib.optional (network == "ethernet") "--with-device=ch3:sock"
      ++ lib.optionals (network == "infiniband") [ "--with-device=ch3:mrail" "--with-rdma=gen2" ]
      ++ lib.optionals (network == "omnipath") ["--with-device=ch3:psm" "--with-psm2=${libpsm2}"]
  
negative.code:     slurm
      openssh
      hwloc
    ] ++ lists.optionals (network == "infiniband") [ rdma-core infiniband-diags opensm ]
      ++ lists.optionals (network == "omnipath") [ libpsm2 libfabric ]
    ;
  
    configureFlags = [
      "--with-pm=hydra"
  