gringo 4.5.4-1 (amd64 binary) in ubuntu xenial

 Current answer set solvers work on variable-free programs. Hence, a
 grounder is needed that, given an input program with first-order
 variables, computes an equivalent ground (variable-free) program.
 .
 This package contains the following tools:
 .
  - gringo: creates lparse-compatible variable-free programs.
  - clingo: stands for clasp on gringo and combines both systems in
    a monolithic way. Its input language is that of gringo and its
    output corresponds to that of clasp.
  - reify: small utility that reifies logic program, given in smodels
    format. It produces a set of facts that can be processed further
    with gringo.