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00040 #include <gecode/driver.hh>
00041 #include <gecode/int.hh>
00042 #include <gecode/minimodel.hh>
00043 #include <gecode/graph.hh>
00044
00045 #ifdef GECODE_HAS_GIST
00046 #include <QtGui>
00047 #endif
00048
00049 using namespace Gecode;
00050
00051
00060 class Warnsdorff : public Brancher {
00061 protected:
00063 ViewArray<Int::IntView> x;
00065 mutable int start;
00067 class Choice : public Gecode::Choice {
00068 public:
00070 int pos;
00072 int val;
00076 Choice(const Brancher& b, int pos0, int val0)
00077 : Gecode::Choice(b,2), pos(pos0), val(val0) {}
00079 virtual size_t size(void) const {
00080 return sizeof(Choice);
00081 }
00082 };
00083
00085 Warnsdorff(Home home, ViewArray<Int::IntView>& xv)
00086 : Brancher(home), x(xv), start(0) {}
00088 Warnsdorff(Space& home, bool share, Warnsdorff& b)
00089 : Brancher(home, share, b), start(b.start) {
00090 x.update(home, share, b.x);
00091 }
00092 public:
00094 virtual bool status(const Space&) const {
00095
00096 for (int n=x.size(); n--; ) {
00097 if (!x[start].assigned())
00098 return true;
00099
00100 start = x[start].val();
00101 }
00102 return false;
00103 }
00105 virtual Gecode::Choice* choice(Space&) {
00106 Int::ViewValues<Int::IntView> iv(x[start]);
00107 int n = iv.val();
00108 unsigned int min = x[n].size();
00109 ++iv;
00110
00111 while (iv()) {
00112 if (x[iv.val()].size() < min) {
00113 n = iv.val();
00114 min = x[n].size();
00115 }
00116 ++iv;
00117 }
00118 return new Choice(*this, start, n);
00119 }
00121 virtual ExecStatus commit(Space& home, const Gecode::Choice& _c,
00122 unsigned int a) {
00123 const Choice& c = static_cast<const Choice&>(_c);
00124 if (a == 0)
00125 return me_failed(x[c.pos].eq(home, c.val)) ? ES_FAILED : ES_OK;
00126 else
00127 return me_failed(x[c.pos].nq(home, c.val)) ? ES_FAILED : ES_OK;
00128 }
00130 virtual Actor* copy(Space& home, bool share) {
00131 return new (home) Warnsdorff(home, share, *this);
00132 }
00134 static void post(Home home, const IntVarArgs& x) {
00135 ViewArray<Int::IntView> xv(home, x);
00136 (void) new (home) Warnsdorff(home, xv);
00137 }
00139 virtual size_t dispose(Space&) {
00140 return sizeof(*this);
00141 }
00142 };
00143
00144
00146 class Knights : public Script {
00147 public:
00149 const int n;
00151 IntVarArray succ;
00153 enum {
00154 PROP_REIFIED,
00155 PROP_CIRCUIT
00156 };
00158 enum {
00159 BRANCH_NAIVE,
00160 BRANCH_WARNSDORFF,
00161 };
00163 int f(int x, int y) const {
00164 return x + y*n;
00165 }
00167 int x(int f) const {
00168 return f % n;
00169 }
00171 int y(int f) const {
00172 return f / n;
00173 }
00175 IntSet neighbors(int i) {
00176 static const int moves[8][2] = {
00177 {-2,-1}, {-2,1}, {-1,-2}, {-1,2}, {1,-2}, {1,2}, {2,-1}, {2,1}
00178 };
00179 int nbs[8]; int n_nbs = 0;
00180 for (int m=0; m<8; m++) {
00181 int nx = x(i) + moves[m][0], ny = y(i) + moves[m][1];
00182 if ((nx >= 0) && (nx < n) && (ny >= 0) && (ny < n))
00183 nbs[n_nbs++] = f(nx,ny);
00184 }
00185 return IntSet(nbs,n_nbs);
00186 }
00188 Knights(const SizeOptions& opt)
00189 : n(opt.size()), succ(*this,n*n,0,n*n-1) {
00190 switch (opt.branching()) {
00191 case BRANCH_NAIVE:
00192 branch(*this, succ, INT_VAR_NONE, INT_VAL_MIN);
00193 break;
00194 case BRANCH_WARNSDORFF:
00195 Warnsdorff::post(*this, succ);
00196 break;
00197 }
00198 }
00200 Knights(bool share, Knights& s) : Script(share,s), n(s.n) {
00201 succ.update(*this, share, s.succ);
00202 }
00204 virtual void
00205 print(std::ostream& os) const {
00206 int* jump = new int[n*n];
00207 {
00208 int j=0;
00209 for (int i=0; i<n*n; i++) {
00210 jump[j]=i; j=succ[j].min();
00211 }
00212 }
00213 os << "\t";
00214 for (int i = 0; i < n; i++) {
00215 for (int j = 0; j < n; j++) {
00216 os.width(3);
00217 os << jump[f(i,j)] << " ";
00218 }
00219 os << std::endl << "\t";
00220 }
00221 os << std::endl;
00222 delete [] jump;
00223 }
00224 };
00225
00236 class KnightsReified : public Knights {
00237 public:
00238 KnightsReified(const SizeOptions& opt) : Knights(opt) {
00239 const int nn = n*n;
00240
00241
00242 IntVarArgs jump(nn);
00243 IntVarArgs pred(nn);
00244
00245 for (int i = nn; i--; ) {
00246 IntVar p(*this,0,nn-1); pred[i]=p;
00247 IntVar j(*this,0,nn-1); jump[i]=j;
00248 }
00249
00250
00251 rel(*this, jump[f(0,0)], IRT_EQ, 0);
00252 rel(*this, jump[f(1,2)], IRT_EQ, 1);
00253
00254 distinct(*this, jump, opt.icl());
00255 channel(*this, succ, pred, opt.icl());
00256
00257 for (int f = 0; f < nn; f++) {
00258 IntSet ds = neighbors(f);
00259 for (IntSetValues i(ds); i(); ++i)
00260 rel(*this,
00261 post(*this, ~(jump[i.val()]-jump[f] == 1)),
00262 BOT_XOR,
00263 post(*this, ~(jump[i.val()]-jump[f] == 1-nn)),
00264 post(*this, ~(succ[f] == i.val())));
00265 dom(*this, pred[f], ds);
00266 dom(*this, succ[f], ds);
00267 rel(*this, succ[f], IRT_NQ, pred[f]);
00268 }
00269 }
00271 KnightsReified(bool share, KnightsReified& s) : Knights(share,s) {}
00273 virtual Space*
00274 copy(bool share) {
00275 return new KnightsReified(share,*this);
00276 }
00277 };
00278
00289 class KnightsCircuit : public Knights {
00290 public:
00291 KnightsCircuit(const SizeOptions& opt) : Knights(opt) {
00292
00293 rel(*this, succ[0], IRT_EQ, f(1,2));
00294
00295 circuit(*this, succ, opt.icl());
00296
00297 for (int f = 0; f < n*n; f++)
00298 dom(*this, succ[f], neighbors(f));
00299 }
00301 KnightsCircuit(bool share, KnightsCircuit& s) : Knights(share,s) {}
00303 virtual Space*
00304 copy(bool share) {
00305 return new KnightsCircuit(share,*this);
00306 }
00307 };
00308
00309 #ifdef GECODE_HAS_GIST
00310
00311 class KnightsInspector : public Gist::Inspector {
00312 protected:
00314 QGraphicsScene* scene;
00316 QMainWindow* mw;
00318 static const int unit = 30;
00319 public:
00321 KnightsInspector(void) : scene(NULL), mw(NULL) {}
00323 virtual void inspect(const Space& s) {
00324 const Knights& k = static_cast<const Knights&>(s);
00325
00326 if (!scene)
00327 initialize();
00328 QList <QGraphicsItem*> itemList = scene->items();
00329 foreach (QGraphicsItem* i, scene->items()) {
00330 scene->removeItem(i);
00331 delete i;
00332 }
00333
00334 for (int i=0; i<k.n; i++) {
00335 for (int j=0; j<k.n; j++) {
00336 scene->addRect(i*unit,j*unit,unit,unit);
00337
00338 QPen pen(Qt::black, 2);
00339 if (!k.succ[i*k.n+j].assigned()) {
00340 pen.setColor(Qt::red);
00341 pen.setStyle(Qt::DotLine);
00342 pen.setWidth(0);
00343 }
00344 for (IntVarValues xv(k.succ[i*k.n+j]); xv(); ++xv) {
00345 int ky = xv.val() % k.n;
00346 int kx = xv.val() / k.n;
00347 scene->addLine(i*unit+unit/2,j*unit+unit/2,
00348 kx*unit+unit/2,ky*unit+unit/2,
00349 pen);
00350 }
00351
00352 }
00353 }
00354 mw->show();
00355 }
00356
00358 void initialize(void) {
00359 mw = new QMainWindow();
00360 scene = new QGraphicsScene();
00361 QGraphicsView* view = new QGraphicsView(scene);
00362 view->setRenderHints(QPainter::Antialiasing);
00363 mw->setCentralWidget(view);
00364 mw->setAttribute(Qt::WA_QuitOnClose, false);
00365 mw->setAttribute(Qt::WA_DeleteOnClose, false);
00366 QAction* closeWindow = new QAction("Close window", mw);
00367 closeWindow->setShortcut(QKeySequence("Ctrl+W"));
00368 mw->connect(closeWindow, SIGNAL(triggered()),
00369 mw, SLOT(close()));
00370 mw->addAction(closeWindow);
00371 }
00372
00374 virtual std::string name(void) { return "Board"; }
00376 virtual void finalize(void) {
00377 delete mw;
00378 mw = NULL;
00379 }
00380 };
00381 #endif GECODE_HAS_GIST
00382
00386 int
00387 main(int argc, char* argv[]) {
00388 SizeOptions opt("Knights");
00389 opt.iterations(100);
00390 opt.size(8);
00391 opt.propagation(Knights::PROP_CIRCUIT);
00392 opt.propagation(Knights::PROP_REIFIED, "reified");
00393 opt.propagation(Knights::PROP_CIRCUIT, "circuit");
00394 opt.branching(Knights::BRANCH_NAIVE);
00395 opt.branching(Knights::BRANCH_NAIVE, "reified");
00396 opt.branching(Knights::BRANCH_WARNSDORFF, "warnsdorff");
00397
00398 #ifdef GECODE_HAS_GIST
00399 KnightsInspector ki;
00400 opt.inspect.click(&ki);
00401 #endif
00402
00403 opt.parse(argc,argv);
00404
00405 if (opt.propagation() == Knights::PROP_REIFIED) {
00406 Script::run<KnightsReified,DFS,SizeOptions>(opt);
00407 } else {
00408 Script::run<KnightsCircuit,DFS,SizeOptions>(opt);
00409 }
00410 return 0;
00411 }
00412
00413
00414