mirror of
https://github.com/Z3Prover/z3
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38 lines
1.1 KiB
Python
38 lines
1.1 KiB
Python
from z3 import *
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from z3.z3util import get_vars
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'''
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Modified from the example in pysmt
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https://github.com/pysmt/pysmt/blob/97088bf3b0d64137c3099ef79a4e153b10ccfda7/examples/efsmt.py
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'''
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def efsmt(ys, phi, maxloops = None):
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"""Solving exists xs. forall ys. phi(x, y)"""
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xs = [x for x in get_vars(phi) if x not in ys]
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E = Solver()
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F = Solver()
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E.add(BoolVal(True))
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loops = 0
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while maxloops is None or loops <= maxloops:
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loops += 1
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eres = E.check()
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if eres == unsat:
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return unsat
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else:
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emodel = E.model()
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sub_phi = substitute(phi, [(x, emodel.eval(x, True)) for x in xs])
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F.push()
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F.add(Not(sub_phi))
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if F.check() == sat:
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fmodel = F.model()
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sub_phi = substitute(phi, [(y, fmodel.eval(y, True)) for y in ys])
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E.add(sub_phi)
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else:
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return sat, [(x, emodel.eval(x, True)) for x in xs]
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F.pop()
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return unknown
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x, y, z = Reals("x y z")
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print(efsmt([y], Implies(And(y > 0, y < 10), y - 2 * x < 7)))
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print(efsmt([y], And(y > 3, x == 1)))
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