black-hole.cc

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Mikael Lagerkvist <lagerkvist@gecode.org>
 *
 *  Copyright:
 *     Mikael Lagerkvist, 2006
 *
 *  Last modified:
 *     $Date: 2008-02-05 10:52:04 +0100 (Tue, 05 Feb 2008) $ by $Author: schulte $
 *     $Revision: 6052 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
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#include "examples/support.hh"

#include "gecode/minimodel.hh"

#include <vector>
#include <algorithm>
#include <sstream>

namespace {
  using std::vector;

  vector<vector<int> > layout;
  vector<int> layer, pile;

  void generate(int seed) {
    // The layout consists of 17 piles of 3 cards each
    layout = vector<vector<int> >(17, vector<int>(3));
    // Deck without the Ace of Spades
    vector<int> deck(51);
    for (int i = 51; i--; ) deck[i] = i+1;
    Support::RandomGenerator rnd(seed+1);
    std::random_shuffle(deck.begin(), deck.end(), rnd);

    // Place cards from deck
    int pos = 0;
    for (int i = 17; i--; )
      for (int j = 3; j--; )
        layout[i][j] = deck[pos++];

    // Location-information for each card
    layer = vector<int>(52);
    pile  = vector<int>(52);
    for (int i = 17; i--; ) {
      for (int j = 3; j--; ) {
        layer[layout[i][j]] = j;
        pile[ layout[i][j]] = i;
      }
    }
  }
}


class BlackHoleBranch : Branching {
  ViewArray<Int::IntView> x;
  mutable int pos, val;
 
  BlackHoleBranch(Space* home, ViewArray<Int::IntView>& xv) 
    : Branching(home), x(xv), pos(-1), val(-1) {}
  BlackHoleBranch(Space* home, bool share, BlackHoleBranch& b) 
    : Branching(home, share, b), pos(b.pos), val(b.val) {
    x.update(home, share, b.x);
  }
  
public:
  virtual bool status(const Space*) const {
    for (pos = 0; pos < x.size(); ++pos) {
      if (!x[pos].assigned()) {
        int w = 4;
        for (Int::ViewValues<Int::IntView> vals(x[pos]); vals(); ++vals) {
          if (layer[vals.val()] < w) {
            val = vals.val();
            if ((w = layer[vals.val()]) == 0) break;
          }
        }
        return true;
      }
    }
    // No non-assigned variables left
    return false;
  }
  virtual BranchingDesc* description(const Space*) const {
    assert(pos >= 0 && pos < x.size() && val >= 1 && val < 52);
    return new PosValDesc<int,2>(this, pos, val);
  }
  virtual ExecStatus commit(Space* home, const BranchingDesc* d, 
                            unsigned int a) {
    const PosValDesc<int,2> *desc = static_cast<const PosValDesc<int,2>*>(d);
    pos = val = -1;
    if (a)
      return me_failed(x[desc->pos()].nq(home, desc->val())) 
        ? ES_FAILED : ES_OK;
    else 
      return me_failed(x[desc->pos()].eq(home, desc->val())) 
        ? ES_FAILED : ES_OK;
  }
  virtual Actor* copy(Space *home, bool share) {
    return new (home) BlackHoleBranch(home, share, *this);
  }
  virtual const char* name(void) const {
    return "BlackHoleBranch";
  }
  static void post(Space* home, IntVarArgs x) {
    ViewArray<Int::IntView> xv(home, x);
    (void) new (home) BlackHoleBranch(home, xv);
  }
};


class BlackHole : public Example {
protected:
  IntVarArray x, 
    y; 

  std::string
  card(int val) {
    const char* suit = "SCHD";
    std::ostringstream o;
    o << std::setw(2) << (1 + (val%13)) << suit[val/13];
    return o.str();
  }

public:
  enum {
    MODEL_NONE,    
    MODEL_SYMMETRY 
  };
  enum {
    PROPAGATION_REIFIED,  
    PROPAGATION_DFA,      
    PROPAGATION_TUPLE_SET 
  };
  BlackHole(const SizeOptions& opt) 
    : x(this, 52, 0,51), y(this, 52, 0,51) 
  {
    // Black ace at bottom
    rel(this, x[0], IRT_EQ, 0);

    // x is order and y is placement
    channel(this, x, y, opt.icl());

    // The placement rules: the absolute value of the difference
    // between two consecutive cards is 1 or 12.
    if (opt.propagation() == PROPAGATION_REIFIED) {
      // Build table for accessing the rank of a card
      IntArgs modtable(52);
      for (int i = 0; i < 52; ++i) {
        modtable[i] = i%13;
      }
      for (int i = 0; i < 51; ++i) {
        IntVar x1(this, 0, 12), x2(this, 0, 12);
        element(this, modtable, x[i], x1);
        element(this, modtable, x[i+1], x2);
        const int dr[2] = {1, 12};
        IntVar diff(this, IntSet(dr, 2));
        post(this, abs(this, minus(this, x1, x2, ICL_DOM), ICL_DOM) 
             == diff, ICL_DOM);
      }
    } else if (opt.propagation() == PROPAGATION_DFA) {
      // Build table for allowed tuples
      REG expression;
      for (int r = 13; r--; ) {
        for (int s1 = 4; s1--; ) {
          for (int s2 = 4; s2--; ) {
            for (int i = -1; i <= 1; i+=2) {
              REG r1 = REG(r+13*s1);
              REG r2 = REG((r+i+52+13*s2)%52);
              REG r = r1 + r2;
              expression |= r;
            }
          }
        }
      }
      DFA table(expression);

      for (int i = 51; i--; ) {
        IntVarArgs iva(2);
        iva[0] = x[i]; iva[1] = x[i+1];
        extensional(this, iva, table);
      }

    } else { // opt.propagation() == PROPAGATION_TUPLE_SET)
      // Build table for allowed tuples
      TupleSet tupleSet;
      for (int r = 13; r--; ) {
        for (int s1 = 4; s1--; ) {
          for (int s2 = 4; s2--; ) {
            for (int i = -1; i <= 1; i+=2) {
              IntArgs t(2);
              t[0] = r+13*s1;
              t[1] = (r+i+52+13*s2)%52;
              tupleSet.add(t);
            }
          }
        }
      }

      for (int i = 51; i--; ) {
        IntVarArgs iva(2);
        iva[0] = x[i]; iva[1] = x[i+1];
        extensional(this, iva, tupleSet, ICL_DOM, opt.pk());
      }
    }
    // A card must be played before the one under it.
    for (int i = 17; i--; )
      for (int j = 2; j--; )
        post(this, y[layout[i][j]] < y[layout[i][j+1]]);

    // Compute and break the conditional symmetries that are dependent
    // on the current layout.
    if (opt.model() == MODEL_SYMMETRY) {
      // For all ranks
      for (int r = 13; r--; ) {
        // For all pairs of suits
        for (int s1 = 4; s1--; ) {
          for (int s2 = s1; s2--; ) {
            int c1 = 13*s1 + r,
              c2 = 13*s2 + r;
            // The ace of spades is already placed
            if (c1 == 0 || c2 == 0) continue;
            // Piles are handled by the rules of the game
            if (pile[c1] == pile[c2]) continue;
            // Get the right order of the cards
            int o1 = c1, o2 = c2;
            if (pile[c1] > pile[c2] && layer[c2] >= layer[c1]) 
              std::swap(o1, o2);
            // cond is the condition for the symmetry
            BoolVarArgs ba(4);
            int pos = 0;
            // Both cards played after the ones on top of them
            for (int i = 0; i < layer[o1]; ++i)
              ba[pos++] = post(this, ~(y[layout[pile[o1]][i]] < y[o2]));
            for (int i = 0; i < layer[o2]; ++i)
              ba[pos++] = post(this, ~(y[layout[pile[o2]][i]] < y[o1]));
            // Both cards played before the ones under them
            for (int i = layer[o1]+1; i < 3; ++i)
              ba[pos++] = post(this, ~(y[o2] < y[layout[pile[o1]][i]]));
            for (int i = layer[o2]+1; i < 3; ++i)
              ba[pos++] = post(this, ~(y[o1] < y[layout[pile[o2]][i]]));
            // Cond holds when all the above holds
            BoolVar cond(this, 0, 1);
            rel(this, BOT_AND, ba, cond);
            
            // If cond is fulfilled, then we can order the cards
            // cond -> (y[o1] < y[o2])
            post(this, tt(!cond || ~(y[o1] < y[o2])));
          }
        }
      }
    }
    
    // Install custom branching
    BlackHoleBranch::post(this, x);      
  }

  virtual void
  print(std::ostream& os) {
    os << "Layout:" << std::endl;
    for (int i = 0; i < 17; i++) {
      for (int j = 0; j < 3; j++)
        os << card(layout[i][j]) << " ";
      if ((i+1) % 3 == 0) 
        os << std::endl;
      else
        os << "\t";
    }
    os << std::endl << std::endl;
    
    os << "Solution:" << std::endl;
    for (int i = 0; i < 52; ++i) {
      os << card(x[i].min()) << " ";
      if ((i + 1) % 13 == 0)
        os << std::endl;
    }
    os << std::endl;
    os << std::endl;
  }

  BlackHole(bool share, BlackHole& s) : Example(share,s) {
    x.update(this, share, s.x);
    y.update(this, share, s.y);
  }
  virtual Space*
  copy(bool share) {
    return new BlackHole(share,*this);
  }
};

int
main(int argc, char* argv[]) {
  SizeOptions opt("Black Hole patience");
  opt.model(BlackHole::MODEL_SYMMETRY);
  opt.model(BlackHole::MODEL_NONE,"none");
  opt.model(BlackHole::MODEL_SYMMETRY,"symmetry");
  opt.propagation(BlackHole::PROPAGATION_DFA);
  opt.propagation(BlackHole::PROPAGATION_REIFIED,
                  "reified", "use reified propagation");
  opt.propagation(BlackHole::PROPAGATION_DFA,
                  "dfa", "use DFA-based extensional propagation");
  opt.propagation(BlackHole::PROPAGATION_TUPLE_SET,
                  "tuple-set", "use TupleSet-based extensional propagation");
  opt.icl(ICL_DOM);
  opt.pk(PK_SPEED);
  opt.parse(argc,argv);
  // Generates the new board
  generate(opt.size());
  Example::run<BlackHole,DFS,SizeOptions>(opt);
  return 0;
}

// STATISTICS: example-any