Question

I have a file containing:

(declare-const a Int)
(declare-const b Int)
(declare-const c Int)
(declare-const d Real)
(declare-const e Real)
(assert (> a (+ b 2)))
(assert (= a (+ (* 2 c) 10)))
(assert (<= (+ c b) 1000))
(assert (>= d e))
(check-sat)
(get-model)

and, according to the online tutorial, running z3 on this file should return:

sat
(model
    (define-fun c () Int
        (- 5))
    (define-fun a () Int
        0)
    (define-fun b () Int
        (- 3))
    (define-fun d ()
        Real 0.0)
    (define-fun e ()
        Real 0.0)
)

So I know this is legal Z3 input. However, whenever I run “z3 [option] ” all I get is error messages no matter what option I choose — including none. Can someone tell me how to correctly invoke Z3 on the input file?

Regards.

Answer 1

Z3 supports many input formats. It uses the file extension to guess which parser will be used. If the extension is .smt2. It will use the SMT 2.0 parser. You can also specify which parser should be used. The option -smt2 will force Z3 to use the SMT 2.0 parser. Finally, Z3 does not enable model construction by default. So, you should use the option MODEL=true, or add the command (set-option :produce-models true) in the beginning of your script.

If you want to use a very old version of Z3, you will have to use SMT 1.0 format.
This format is described at: http://goedel.cs.uiowa.edu/smtlib/papers/format-v1.2-r06.08.30.pdf

That being said, I strongly encourage you to upgrade. The SMT 1.0 is not very user friendly, and most documentation/tutorials for SMT are in SMT 2.0 format.

Here is your example in this format:

(benchmark file
  :extrafuns ((a Int) (b Int) (c Int) (d Real) (e Real))
  :assumption (> a (+ b 2))
  :assumption (= a (+ (* 2 c) 10))
  :assumption (<= (+ c b) 1000)
  :assumption (>= d e)
  :formula true)