example3.cpp

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// 
// Copyright (c) 2014, Benjamin Kaufmann
// 
// This file is part of Clasp. See http://www.cs.uni-potsdam.de/clasp/ 
// 
// Clasp is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// Clasp is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with Clasp; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//
#if WITH_THREADS
// Add the libclasp directory to the list of 
// include directoies of your build system.
#include <clasp/clasp_facade.h>
#include <clasp/solver.h>
#include "example.h"

// This example uses the ClaspFacade to compute
// the stable models of the program
//    a :- not b.
//    b :- not a.
//
// It is similar to example2() but uses the facade's asynchronous
// interface in order to get the models one by one.
void example3() {
        // See example2()
        Clasp::ClaspConfig config;
        config.enumerate.numModels = 0;
        
        // The "interface" to the clasp library.
        Clasp::ClaspFacade libclasp;

        // See example2()
        Clasp::Asp::LogicProgram& asp = libclasp.startAsp(config);
        asp.setAtomName(1, "a");
        asp.setAtomName(2, "b");
        asp.startRule(Clasp::Asp::BASICRULE).addHead(1).addToBody(2, false).endRule();
        asp.startRule(Clasp::Asp::BASICRULE).addHead(2).addToBody(1, false).endRule();
        
        // We are done with problem setup. 
        // Prepare the problem for solving.
        libclasp.prepare();

        // Start the asynchronous solving process.
        Clasp::ClaspFacade::AsyncResult it = libclasp.startSolveAsync();
        // Get models one by one until iterator is exhausted.
        while (!it.end()) {
                printModel(libclasp.ctx.symbolTable(), it.model());
                // Advance iterator to next model.
                it.next();
        }
        std::cout << "No more models!" << std::endl;
}
#endif