mirror of
https://github.com/AdaCore/cvc5.git
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7ff15aa749
This refactors the Solver class in the java API to extend AbstractPointer similar to other cvc5 classes. It also cleans up redundant code for Abstract pointers. and adds Context.deletePointers to java examples as mentioned in issue #10052.
201 lines
7.8 KiB
Java
201 lines
7.8 KiB
Java
/******************************************************************************
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* Top contributors (to current version):
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* Mudathir Mohamed, Aina Niemetz, Andres Noetzli
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*
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* This file is part of the cvc5 project.
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*
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* Copyright (c) 2009-2022 by the authors listed in the file AUTHORS
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* in the top-level source directory and their institutional affiliations.
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* All rights reserved. See the file COPYING in the top-level source
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* directory for licensing information.
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* ****************************************************************************
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*
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* A simple demonstration of the api capabilities of cvc5.
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*
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*/
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import io.github.cvc5.*;
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import java.math.BigInteger;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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public class QuickStart
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{
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public static void main(String args[]) throws CVC5ApiException
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{
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// Create a solver
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Solver solver = new Solver();
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{
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// We will ask the solver to produce models and unsat cores,
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// hence these options should be turned on.
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//! [docs-java-quickstart-1 start]
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solver.setOption("produce-models", "true");
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solver.setOption("produce-unsat-cores", "true");
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//! [docs-java-quickstart-1 end]
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// The simplest way to set a logic for the solver is to choose "ALL".
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// This enables all logics in the solver.
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// Alternatively, "QF_ALL" enables all logics without quantifiers.
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// To optimize the solver's behavior for a more specific logic,
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// use the logic name, e.g. "QF_BV" or "QF_AUFBV".
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// Set the logic
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//! [docs-java-quickstart-2 start]
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solver.setLogic("ALL");
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//! [docs-java-quickstart-2 end]
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// In this example, we will define constraints over reals and integers.
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// Hence, we first obtain the corresponding sorts.
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//! [docs-java-quickstart-3 start]
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Sort realSort = solver.getRealSort();
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Sort intSort = solver.getIntegerSort();
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//! [docs-java-quickstart-3 end]
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// x and y will be real variables, while a and b will be integer variables.
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// Formally, their cpp type is Term,
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// and they are called "constants" in SMT jargon:
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//! [docs-java-quickstart-4 start]
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Term x = solver.mkConst(realSort, "x");
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Term y = solver.mkConst(realSort, "y");
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Term a = solver.mkConst(intSort, "a");
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Term b = solver.mkConst(intSort, "b");
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//! [docs-java-quickstart-4 end]
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// Our constraints regarding x and y will be:
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//
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// (1) 0 < x
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// (2) 0 < y
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// (3) x + y < 1
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// (4) x <= y
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//
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//! [docs-java-quickstart-5 start]
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// Formally, constraints are also terms. Their sort is Boolean.
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// We will construct these constraints gradually,
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// by defining each of their components.
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// We start with the constant numerals 0 and 1:
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Term zero = solver.mkReal(0);
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Term one = solver.mkReal(1);
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// Next, we construct the term x + y
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Term xPlusY = solver.mkTerm(Kind.ADD, x, y);
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// Now we can define the constraints.
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// They use the operators +, <=, and <.
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// In the API, these are denoted by ADD, LEQ, and LT.
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// A list of available operators is available in:
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// src/api/cpp/cvc5_kind.h
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Term constraint1 = solver.mkTerm(Kind.LT, zero, x);
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Term constraint2 = solver.mkTerm(Kind.LT, zero, y);
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Term constraint3 = solver.mkTerm(Kind.LT, xPlusY, one);
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Term constraint4 = solver.mkTerm(Kind.LEQ, x, y);
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// Now we assert the constraints to the solver.
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solver.assertFormula(constraint1);
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solver.assertFormula(constraint2);
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solver.assertFormula(constraint3);
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solver.assertFormula(constraint4);
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//! [docs-java-quickstart-5 end]
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// Check if the formula is satisfiable, that is,
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// are there real values for x and y that satisfy all the constraints?
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//! [docs-java-quickstart-6 start]
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Result r1 = solver.checkSat();
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//! [docs-java-quickstart-6 end]
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// The result is either SAT, UNSAT, or UNKNOWN.
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// In this case, it is SAT.
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//! [docs-java-quickstart-7 start]
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System.out.println("expected: sat");
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System.out.println("result: " + r1);
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//! [docs-java-quickstart-7 end]
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// We can get the values for x and y that satisfy the constraints.
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//! [docs-java-quickstart-8 start]
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Term xVal = solver.getValue(x);
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Term yVal = solver.getValue(y);
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//! [docs-java-quickstart-8 end]
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// It is also possible to get values for compound terms,
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// even if those did not appear in the original formula.
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//! [docs-java-quickstart-9 start]
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Term xMinusY = solver.mkTerm(Kind.SUB, x, y);
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Term xMinusYVal = solver.getValue(xMinusY);
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//! [docs-java-quickstart-9 end]
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// Further, we can convert the values to java types
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//! [docs-java-quickstart-10 start]
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Pair<BigInteger, BigInteger> xPair = xVal.getRealValue();
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Pair<BigInteger, BigInteger> yPair = yVal.getRealValue();
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Pair<BigInteger, BigInteger> xMinusYPair = xMinusYVal.getRealValue();
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System.out.println("value for x: " + xPair.first + "/" + xPair.second);
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System.out.println("value for y: " + yPair.first + "/" + yPair.second);
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System.out.println("value for x - y: " + xMinusYPair.first + "/" + xMinusYPair.second);
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//! [docs-java-quickstart-10 end]
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// Another way to independently compute the value of x - y would be
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// to perform the (rational) arithmetic manually.
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// However, for more complex terms,
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// it is easier to let the solver do the evaluation.
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//! [docs-java-quickstart-11 start]
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Pair<BigInteger, BigInteger> xMinusYComputed =
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new Pair(xPair.first.multiply(yPair.second).subtract(xPair.second.multiply(yPair.first)),
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xPair.second.multiply(yPair.second));
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BigInteger g = xMinusYComputed.first.gcd(xMinusYComputed.second);
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xMinusYComputed = new Pair(xMinusYComputed.first.divide(g), xMinusYComputed.second.divide(g));
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if (xMinusYComputed.equals(xMinusYPair))
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{
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System.out.println("computed correctly");
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}
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else
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{
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System.out.println("computed incorrectly");
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}
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//! [docs-java-quickstart-11 end]
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// Next, we will check satisfiability of the same formula,
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// only this time over integer variables a and b.
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// We start by resetting assertions added to the solver.
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//! [docs-java-quickstart-12 start]
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solver.resetAssertions();
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//! [docs-java-quickstart-12 end]
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// Next, we assert the same assertions above with integers.
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// This time, we inline the construction of terms
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// to the assertion command.
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//! [docs-java-quickstart-13 start]
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solver.assertFormula(solver.mkTerm(Kind.LT, solver.mkInteger(0), a));
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solver.assertFormula(solver.mkTerm(Kind.LT, solver.mkInteger(0), b));
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solver.assertFormula(
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solver.mkTerm(Kind.LT, solver.mkTerm(Kind.ADD, a, b), solver.mkInteger(1)));
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solver.assertFormula(solver.mkTerm(Kind.LEQ, a, b));
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//! [docs-java-quickstart-13 end]
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// We check whether the revised assertion is satisfiable.
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//! [docs-java-quickstart-14 start]
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Result r2 = solver.checkSat();
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// This time the formula is unsatisfiable
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System.out.println("expected: unsat");
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System.out.println("result: " + r2);
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//! [docs-java-quickstart-14 end]
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// We can query the solver for an unsatisfiable core, i.e., a subset
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// of the assertions that is already unsatisfiable.
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//! [docs-java-quickstart-15 start]
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List<Term> unsatCore = Arrays.asList(solver.getUnsatCore());
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System.out.println("unsat core size: " + unsatCore.size());
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System.out.println("unsat core: ");
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for (Term t : unsatCore)
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{
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System.out.println(t);
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}
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//! [docs-java-quickstart-15 end]
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}
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Context.deletePointers();
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}
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}
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