Alg_OBV.h

/*!
 * \author Ruben Martins - ruben@sat.inesc-id.pt
 *
 * @section LICENSE
 *
 * Open-WBO, Copyright (c) 2013-2017, Ruben Martins, Vasco Manquinho, Ines Lynce
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */

#ifndef Alg_OBV_h
#define Alg_OBV_h

#ifdef SIMP
#include "simp/SimpSolver.h"
#else
#include "core/Solver.h"
#endif

#include "../Encoder.h"
#include "../MaxSAT.h"
#include <map>
#include <set>
#include <vector>

using NSPACE::vec;
using NSPACE::Lit;

namespace openwbo {

//=================================================================================================
class OBV : public MaxSAT {

public:
  OBV(int verb = _VERBOSITY_MINIMAL_, int enc = _CARD_MTOTALIZER_, int limit = 10000, int iterations = 1000, bool local = false)
      : solver(NULL) {
    verbosity = verb;
    encoding = enc;
    encoder.setCardEncoding(enc);
    _limit = limit;
    _iterations = iterations;
    _local = local;
    _budget = true;
  }

  ~OBV() {
    if (solver != NULL)
      delete solver;

    objFunction.clear();
    coeffs.clear();
  }

  void search(); // Linear search.

  // Print solver configuration.
  void printConfiguration() {

    printf("c ==========================================[ Solver Settings "
           "]============================================\n");
    printf("c |                                                                "
           "                                       |\n");
    printf("c |  Algorithm: %23s                                             "
           "                      |\n",
           "OBV");
    print_Card_configuration(encoding);
    printf("c |  Limit number conflicts: %10d                                 "
           "                                  |\n", _limit);
    printf("c |  Limit number iterations: %9d                                 "
      "                                  |\n", _iterations);
    if (_local)
      printf("c |  Global limit number conflicts:   F                          "
        "                                         |\n");
    else
      printf("c |  Global limit number conflicts:   T                          "
        "                                         |\n");
    printf("c |                                                                "
           "                                       |\n");
  }

protected:
  // Rebuild MaxSAT solver
  //
  // Rebuild MaxSAT solver with BMO algorithm.
  Solver *rebuildBMO(vec<vec<Lit>> &functions, vec<int> &weights,
                     uint64_t currentWeight);
  Solver *rebuildSolver(uint64_t min_weight = 1); // Rebuild MaxSAT solver.

  // Linear search algorithms.
  //
  void normalSearch(); // Classic linear search algorithm.
  void bmoSearch();    // Linear search algorithm with lexicographical order.

  // Other
  void initRelaxation(); // Relaxes soft clauses.

  void MrsBeaver();

  uint64_t MrsBeaver(Solver * solver, int iterations, int conflicts, uint64_t ub);
  uint64_t obv_bs(Solver * solver, std::vector<Lit>& outputs, uint64_t ub, int conflicts);
  uint64_t ums_obv_bs(Solver * solver, std::vector<Lit>& outputs, uint64_t ub, int conflicts);

  Solver *solver;  // SAT Solver used as a black box.
  Encoder encoder; // Interface for the encoder of constraints to CNF.
  int encoding;    // Encoding for cardinality constraints.

  int _limit;
  int _iterations;
  bool _local;
  bool _budget;

  vec<lbool> model_all;

  bool bmoMode;  // Enables BMO mode.
  bool allFalse; // Forces relaxation variables to be false.

  vec<Lit> objFunction; // Literals to be used in the constraint that excludes
                        // models.
  vec<uint64_t> coeffs; // Coefficients of the literals that are used in the
                        // constraint that excludes models.

  bool is_bmo; // Stores if the formula is BMO or not.
};
} // namespace openwbo

#endif