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/********************* */
/*! \file combination.cpp
** \verbatim
** Top contributors (to current version):
** Tim King, Aina Niemetz, Makai Mann
** This file is part of the CVC4 project.
** Copyright (c) 2009-2020 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.\endverbatim
**
** \brief A simple demonstration of the capabilities of CVC4
**
** A simple demonstration of how to use uninterpreted functions, combining this
** with arithmetic, and extracting a model at the end of a satisfiable query.
** The model is displayed using getValue().
**/
#include <iostream>
#include <cvc4/cvc4.h>
using namespace std;
using namespace CVC4;
void prefixPrintGetValue(SmtEngine& smt, Expr e, int level = 0){
for(int i = 0; i < level; ++i){ cout << '-'; }
cout << "smt.getValue(" << e << ") -> " << smt.getValue(e) << endl;
if(e.hasOperator() && e.getOperator().getKind() != kind::BUILTIN){
prefixPrintGetValue(smt, e.getOperator(), level + 1);
}
for(Expr::const_iterator term_i = e.begin(), term_end = e.end();
term_i != term_end; ++term_i)
{
Expr curr = *term_i;
prefixPrintGetValue(smt, curr, level + 1);
}
}
int main() {
ExprManager em;
SmtEngine smt(&em);
smt.setOption("produce-models", true); // Produce Models
smt.setOption("output-language", "cvc4"); // Set the output-language to CVC's
smt.setOption("dag-thresh", 0); //Disable dagifying the output
smt.setLogic(string("QF_UFLIRA"));
// Sorts
SortType u = em.mkSort("u");
Type integer = em.integerType();
Type boolean = em.booleanType();
Type uToInt = em.mkFunctionType(u, integer);
Type intPred = em.mkFunctionType(integer, boolean);
// Variables
Expr x = em.mkVar("x", u);
Expr y = em.mkVar("y", u);
// Functions
Expr f = em.mkVar("f", uToInt);
Expr p = em.mkVar("p", intPred);
// Constants
Expr zero = em.mkConst(Rational(0));
Expr one = em.mkConst(Rational(1));
// Terms
Expr f_x = em.mkExpr(kind::APPLY_UF, f, x);
Expr f_y = em.mkExpr(kind::APPLY_UF, f, y);
Expr sum = em.mkExpr(kind::PLUS, f_x, f_y);
Expr p_0 = em.mkExpr(kind::APPLY_UF, p, zero);
Expr p_f_y = em.mkExpr(kind::APPLY_UF, p, f_y);
// Construct the assumptions
Expr assumptions =
em.mkExpr(kind::AND,
em.mkExpr(kind::LEQ, zero, f_x), // 0 <= f(x)
em.mkExpr(kind::LEQ, zero, f_y), // 0 <= f(y)
em.mkExpr(kind::LEQ, sum, one), // f(x) + f(y) <= 1
p_0.notExpr(), // not p(0)
p_f_y); // p(f(y))
smt.assertFormula(assumptions);
cout << "Given the following assumptions:" << endl
<< assumptions << endl
<< "Prove x /= y is entailed. "
<< "CVC4 says: " << smt.checkEntailed(em.mkExpr(kind::DISTINCT, x, y))
<< "." << endl;
cout << "Now we call checksat on a trivial query to show that" << endl
<< "the assumptions are satisfiable: "
<< smt.checkSat(em.mkConst(true)) << "."<< endl;
cout << "Finally, after a SAT call, we recursively call smt.getValue(...) on "
<< "all of the assumptions to see what the satisfying model looks like."
<< endl;
prefixPrintGetValue(smt, assumptions);
return 0;
}
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