Using ProB with KODKOD

As of version 1.3.5 ProB can make use of Kodkod as an alternate way of solving constraints.

How to enable Kodkod

For the command-line version you need to call prob as follows:

probcli -p KODKOD TRUE

Note: to experiment with Kodkod you may want to try out the command:

probcli -p KODKOD TRUE -repl

For the ProB Tcl/Tk Version you should select the menu command "Enable Kodkod for Properties" in the Preferences menu.

What can be translated

  • Types:
    • Basic Types: Deferred Sets, enumerated sets, integers, booleans
    • Sets of basic types
    • Relations between basic types
    • Higher-order types (sets of sets) are not supported
  • Operators:
    • Predicates: &, or, =>, <=>, not, !, #, =, /=
    • Booleans: TRUE, FALSE, BOOL, bool(...)
    • Sets: {..,...} {x|P}, POW, card, Cartesian product, \/, /\, -, :, /:, /<:, <<: /<<:
    • Numbers: n..m, >, <, >=, <=, +, -, *, SIGMA(x).(P|x)
    • Relations: <->, |->, dom, ran, id, <|, <<|, |>, |>>, ~, [...], <+, prj1, prj2, closure1
    • x : S+->T, x:S-->T, ..., lambda
    • currently no operations on sequences are supported
  • Some limitations:
    • If integers are used, a predicate can only be translated if a static analysis can estimate the interval of its possible values.
    • Generally only complete predicates are translated or nothing at all, unless you set the KODKOD_ONLY_FULL preference to FALSE.

When is the Kokod translation used

  • for solving PROPERTIES
  • constraint-based assertion checking (-cbc_assertions command for probcli or the "Check Assertions on Constants" command in the menu Verify -> Constraint-Based Checking)
  • in the Eval Console in the ProB Tcl/Tk version
  • for the REPL in probcli (probcli -p KODKOD TRUE -repl)

More details