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#!/usr/bin/env python
###############################################################################
# Top contributors (to current version):
# Yoni Zohar, Aina Niemetz, Daniel Larraz
#
# This file is part of the cvc5 project.
#
# Copyright (c) 2009-2025 by the authors listed in the file AUTHORS
# in the top-level source directory and their institutional affiliations.
# All rights reserved. See the file COPYING in the top-level source
# directory for licensing information.
# #############################################################################
#
# A simple demonstration of the api capabilities of cvc5, adapted from quickstart.cpp
##
import cvc5
from cvc5 import Kind
if __name__ == "__main__":
# Create a term manager
#! [docs-python-quickstart-0 start]
tm = cvc5.TermManager()
#! [docs-python-quickstart-0 end]
# Create a solver
#! [docs-python-quickstart-1 start]
solver = cvc5.Solver(tm)
#! [docs-python-quickstart-1 end]
# We will ask the solver to produce models and unsat cores,
# hence these options should be turned on.
#! [docs-python-quickstart-2 start]
solver.setOption("produce-models", "true")
solver.setOption("produce-unsat-cores", "true")
#! [docs-python-quickstart-2 end]
# The simplest way to set a logic for the solver is to choose "ALL".
# This enables all logics in the solver.
# Alternatively, "QF_ALL" enables all logics without quantifiers.
# To optimize the solver's behavior for a more specific logic,
# use the logic name, e.g. "QF_BV" or "QF_AUFBV".
# Set the logic
#! [docs-python-quickstart-3 start]
solver.setLogic("ALL")
#! [docs-python-quickstart-3 end]
# In this example, we will define constraints over reals and integers.
# Hence, we first obtain the corresponding sorts.
#! [docs-python-quickstart-4 start]
realSort = tm.getRealSort()
intSort = tm.getIntegerSort()
#! [docs-python-quickstart-4 end]
# x and y will be real variables, while a and b will be integer variables.
# Formally, their python type is Term,
# and they are called "constants" in SMT jargon:
#! [docs-python-quickstart-5 start]
x = tm.mkConst(realSort, "x")
y = tm.mkConst(realSort, "y")
a = tm.mkConst(intSort, "a")
b = tm.mkConst(intSort, "b")
#! [docs-python-quickstart-5 end]
# Our constraints regarding x and y will be:
#
# (1) 0 < x
# (2) 0 < y
# (3) x + y < 1
# (4) x <= y
#
#! [docs-python-quickstart-6 start]
# Formally, constraints are also terms. Their sort is Boolean.
# We will construct these constraints gradually,
# by defining each of their components.
# We start with the constant numerals 0 and 1:
zero = tm.mkReal(0)
one = tm.mkReal(1)
# Next, we construct the term x + y
xPlusY = tm.mkTerm(Kind.ADD, x, y)
# Now we can define the constraints.
# They use the operators +, <=, and <.
# In the API, these are denoted by Plus, Leq, and Lt.
constraint1 = tm.mkTerm(Kind.LT, zero, x)
constraint2 = tm.mkTerm(Kind.LT, zero, y)
constraint3 = tm.mkTerm(Kind.LT, xPlusY, one)
constraint4 = tm.mkTerm(Kind.LEQ, x, y)
# Now we assert the constraints to the solver.
solver.assertFormula(constraint1)
solver.assertFormula(constraint2)
solver.assertFormula(constraint3)
solver.assertFormula(constraint4)
#! [docs-python-quickstart-6 end]
# Check if the formula is satisfiable, that is,
# are there real values for x and y that satisfy all the constraints?
#! [docs-python-quickstart-7 start]
r1 = solver.checkSat()
#! [docs-python-quickstart-7 end]
# The result is either SAT, UNSAT, or UNKNOWN.
# In this case, it is SAT.
#! [docs-python-quickstart-8 start]
print("expected: sat")
print("result: ", r1)
#! [docs-python-quickstart-8 end]
# We can get the values for x and y that satisfy the constraints.
#! [docs-python-quickstart-9 start]
xVal = solver.getValue(x)
yVal = solver.getValue(y)
#! [docs-python-quickstart-9 end]
# It is also possible to get values for compound terms,
# even if those did not appear in the original formula.
#! [docs-python-quickstart-10 start]
xMinusY = tm.mkTerm(Kind.SUB, x, y)
xMinusYVal = solver.getValue(xMinusY)
#! [docs-python-quickstart-10 end]
# We can now obtain the values as python values
#! [docs-python-quickstart-11 start]
xPy = xVal.getRealValue()
yPy = yVal.getRealValue()
xMinusYPy = xMinusYVal.getRealValue()
print("value for x: ", xPy)
print("value for y: ", yPy)
print("value for x - y: ", xMinusYPy)
#! [docs-python-quickstart-11 end]
# Another way to independently compute the value of x - y would be
# to use the python minus operator instead of asking the solver.
# However, for more complex terms,
# it is easier to let the solver do the evaluation.
#! [docs-python-quickstart-12 start]
xMinusYComputed = xPy - yPy
if xMinusYComputed == xMinusYPy:
print("computed correctly")
else:
print("computed incorrectly")
#! [docs-python-quickstart-12 end]
# Further, we can convert the values to strings
#! [docs-python-quickstart-13 start]
xStr = str(xPy)
yStr = str(yPy)
xMinusYStr = str(xMinusYPy)
#! [docs-python-quickstart-13 end]
# Next, we will check satisfiability of the same formula,
# only this time over integer variables a and b.
# We start by resetting assertions added to the solver.
#! [docs-python-quickstart-14 start]
solver.resetAssertions()
#! [docs-python-quickstart-14 end]
# Next, we assert the same assertions above with integers.
# This time, we inline the construction of terms
# to the assertion command.
#! [docs-python-quickstart-15 start]
solver.assertFormula(tm.mkTerm(Kind.LT, tm.mkInteger(0), a))
solver.assertFormula(tm.mkTerm(Kind.LT, tm.mkInteger(0), b))
solver.assertFormula(
tm.mkTerm(
Kind.LT, tm.mkTerm(Kind.ADD, a, b), tm.mkInteger(1)))
solver.assertFormula(tm.mkTerm(Kind.LEQ, a, b))
#! [docs-python-quickstart-15 end]
# We check whether the revised assertion is satisfiable.
#! [docs-python-quickstart-16 start]
r2 = solver.checkSat()
#! [docs-python-quickstart-16 end]
# This time the formula is unsatisfiable
#! [docs-python-quickstart-17 start]
print("expected: unsat")
print("result:", r2)
#! [docs-python-quickstart-17 end]
# We can query the solver for an unsatisfiable core, i.e., a subset
# of the assertions that is already unsatisfiable.
#! [docs-python-quickstart-18 start]
unsatCore = solver.getUnsatCore()
print("unsat core size:", len(unsatCore))
print("unsat core:", unsatCore)
#! [docs-python-quickstart-18 end]
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