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I am playing with the CVC5 example at https://github.com/cvc5/cvc5/blob/main/examples/api/python/pythonic/linear_arith.py.

from cvc5.pythonic import *

slv = SolverFor('QF_LIRA')

x = Int('x')
y = Real('y')

slv += And(x >= 3 * y, x <= y, -2 < x)
slv.push()
print(slv.check(y-x <= 2/3))
slv.pop()
slv.push()
slv += y-x == 2/3
print(slv.check())
slv.pop()

It works as it is supposed to work.

However, whenever I try to print the content of the formula (i.e., print(slv)), it raises the following error: Cannot print: Kind.CONST_INTEGER

The same happens with literals that compound the formula: i.e., print(x >= 3); but not with variables: print(x) returns x.

I would like to have this printing capability, since Z3 allows it and I am trying my (originally-in-Z3-made) implementation with different SMT sovlers. Any idea?

Note that print(slv) does return info ([]), when it is empty. I tried using str(), but the error persists and indeed I guess print() uses str() before printing.

PS: I am using CVC5, should I use CVC4 or is CVC5 mature enough?

Theo Deep
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1 Answers1

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I think this is a bug. You should report it to the CVC5 folks at https://github.com/cvc5/cvc5/issues. (i.e., they should be able to handle this case just fine.)

In the interim, you can use the following workaround:

print(slv.sexpr())

which prints:

(and (let ((_let_1 (to_real x))) (and (>= _let_1 (* 3.0 y)) (<= _let_1 y) (> x (- 2)))))

which takes a bit of squinting to see that this is what you asserted, but it should do the trick.

alias
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  • Yep, the only thing that 'dirties' the result are those 'let's, but it will make it :)) I will ask the question. – Theo Deep Dec 07 '22 at 20:29