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mult.hpp

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00001 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
00002 /*
00003  *  Main authors:
00004  *     Christian Schulte <schulte@gecode.org>
00005  *
00006  *  Copyright:
00007  *     Christian Schulte, 2004
00008  *
00009  *  This file is part of Gecode, the generic constraint
00010  *  development environment:
00011  *     http://www.gecode.org
00012  *
00013  *  Permission is hereby granted, free of charge, to any person obtaining
00014  *  a copy of this software and associated documentation files (the
00015  *  "Software"), to deal in the Software without restriction, including
00016  *  without limitation the rights to use, copy, modify, merge, publish,
00017  *  distribute, sublicense, and/or sell copies of the Software, and to
00018  *  permit persons to whom the Software is furnished to do so, subject to
00019  *  the following conditions:
00020  *
00021  *  The above copyright notice and this permission notice shall be
00022  *  included in all copies or substantial portions of the Software.
00023  *
00024  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00025  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00026  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00027  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00028  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00029  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00030  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00031  *
00032  */
00033 
00034 #include <cmath>
00035 #include <climits>
00036 
00037 #include <gecode/int/div.hh>
00038 #include <gecode/int/support-values.hh>
00039 
00040 namespace Gecode { namespace Int { namespace Arithmetic {
00041 
00042   /*
00043    * Arithmetic help functions
00044    *
00045    */
00047   forceinline long long int
00048   mll(long long int x, long long int y) {
00049     return x*y;
00050   }
00052   forceinline long long int
00053   ll(int x) {
00054     return static_cast<long long int>(x);
00055   }
00057   forceinline long long int
00058   ill(int x) {
00059     return static_cast<long long int>(x) + 1;
00060   }
00062   forceinline long long int
00063   dll(int x) {
00064     return static_cast<long long int>(x) - 1;
00065   }
00066 
00068   template<class View>
00069   forceinline bool
00070   pos(const View& x) {
00071     return x.min() > 0;
00072   }
00074   template<class View>
00075   forceinline bool
00076   neg(const View& x) {
00077     return x.max() < 0;
00078   }
00080   template<class View>
00081   forceinline bool
00082   any(const View& x) {
00083     return (x.min() <= 0) && (x.max() >= 0);
00084   }
00085 
00086 
00087   /*
00088    * Propagator for x * y = x
00089    *
00090    */
00091 
00092   template<class View, PropCond pc>
00093   forceinline
00094   MultZeroOne<View,pc>::MultZeroOne(Home home, View x0, View x1)
00095     : BinaryPropagator<View,pc>(home,x0,x1) {}
00096 
00097   template<class View, PropCond pc>
00098   forceinline RelTest
00099   MultZeroOne<View,pc>::equal(View x, int n) {
00100     if (pc == PC_INT_DOM) {
00101       return rtest_eq_dom(x,n);
00102     } else {
00103       return rtest_eq_bnd(x,n);
00104     }
00105   }
00106 
00107   template<class View, PropCond pc>
00108   forceinline ExecStatus
00109   MultZeroOne<View,pc>::post(Home home, View x0, View x1) {
00110     switch (equal(x0,0)) {
00111     case RT_FALSE:
00112       GECODE_ME_CHECK(x1.eq(home,1));
00113       break;
00114     case RT_TRUE:
00115       break;
00116     case RT_MAYBE:
00117       switch (equal(x1,1)) {
00118       case RT_FALSE:
00119         GECODE_ME_CHECK(x0.eq(home,0));
00120         break;
00121       case RT_TRUE:
00122         break;
00123       case RT_MAYBE:
00124         (void) new (home) MultZeroOne<View,pc>(home,x0,x1);
00125         break;
00126       default: GECODE_NEVER;
00127       }
00128       break;
00129     default: GECODE_NEVER;
00130     }
00131     return ES_OK;
00132   }
00133 
00134   template<class View, PropCond pc>
00135   forceinline
00136   MultZeroOne<View,pc>::MultZeroOne(Space& home, MultZeroOne<View,pc>& p)
00137     : BinaryPropagator<View,pc>(home,p) {}
00138 
00139   template<class View, PropCond pc>
00140   Actor*
00141   MultZeroOne<View,pc>::copy(Space& home) {
00142     return new (home) MultZeroOne<View,pc>(home,*this);
00143   }
00144 
00145   template<class View, PropCond pc>
00146   ExecStatus
00147   MultZeroOne<View,pc>::propagate(Space& home, const ModEventDelta&) {
00148     switch (equal(x0,0)) {
00149     case RT_FALSE:
00150       GECODE_ME_CHECK(x1.eq(home,1));
00151       break;
00152     case RT_TRUE:
00153       break;
00154     case RT_MAYBE:
00155       switch (equal(x1,1)) {
00156       case RT_FALSE:
00157         GECODE_ME_CHECK(x0.eq(home,0));
00158         break;
00159       case RT_TRUE:
00160         break;
00161       case RT_MAYBE:
00162         return ES_FIX;
00163       default: GECODE_NEVER;
00164       }
00165       break;
00166     default: GECODE_NEVER;
00167     }
00168     return home.ES_SUBSUMED(*this);
00169   }
00170 
00171 
00172   /*
00173    * Positive bounds consistent multiplication
00174    *
00175    */
00176   template<class VA, class VB, class VC>
00177   forceinline ExecStatus
00178   prop_mult_plus_bnd(Space& home, Propagator& p, VA x0, VB x1, VC x2) {
00179     assert(pos(x0) && pos(x1) && pos(x2));
00180     bool mod;
00181     do {
00182       mod = false;
00183       {
00184         ModEvent me = x2.lq(home,mll(x0.max(),x1.max()));
00185         if (me_failed(me)) return ES_FAILED;
00186         mod |= me_modified(me);
00187       }
00188       {
00189         ModEvent me = x2.gq(home,mll(x0.min(),x1.min()));
00190         if (me_failed(me)) return ES_FAILED;
00191         mod |= me_modified(me);
00192       }
00193       {
00194         ModEvent me = x0.lq(home,floor_div_pp(x2.max(),x1.min()));
00195         if (me_failed(me)) return ES_FAILED;
00196         mod |= me_modified(me);
00197       }
00198       {
00199         ModEvent me = x0.gq(home,ceil_div_pp(x2.min(),x1.max()));
00200         if (me_failed(me)) return ES_FAILED;
00201         mod |= me_modified(me);
00202       }
00203       {
00204         ModEvent me = x1.lq(home,floor_div_pp(x2.max(),x0.min()));
00205         if (me_failed(me)) return ES_FAILED;
00206         mod |= me_modified(me);
00207       }
00208       {
00209         ModEvent me = x1.gq(home,ceil_div_pp(x2.min(),x0.max()));
00210         if (me_failed(me)) return ES_FAILED;
00211         mod |= me_modified(me);
00212       }
00213     } while (mod);
00214     return x0.assigned() && x1.assigned() ?
00215       home.ES_SUBSUMED(p) : ES_FIX;
00216   }
00217 
00218   template<class VA, class VB, class VC>
00219   forceinline
00220   MultPlusBnd<VA,VB,VC>::MultPlusBnd(Home home, VA x0, VB x1, VC x2)
00221     : MixTernaryPropagator<VA,PC_INT_BND,VB,PC_INT_BND,VC,PC_INT_BND>
00222   (home,x0,x1,x2) {}
00223 
00224   template<class VA, class VB, class VC>
00225   forceinline
00226   MultPlusBnd<VA,VB,VC>::MultPlusBnd(Space& home, MultPlusBnd<VA,VB,VC>& p)
00227     : MixTernaryPropagator<VA,PC_INT_BND,VB,PC_INT_BND,VC,PC_INT_BND>
00228   (home,p) {}
00229 
00230   template<class VA, class VB, class VC>
00231   Actor*
00232   MultPlusBnd<VA,VB,VC>::copy(Space& home) {
00233     return new (home) MultPlusBnd<VA,VB,VC>(home,*this);
00234   }
00235 
00236   template<class VA, class VB, class VC>
00237   ExecStatus
00238   MultPlusBnd<VA,VB,VC>::propagate(Space& home, const ModEventDelta&) {
00239     return prop_mult_plus_bnd<VA,VB,VC>(home,*this,x0,x1,x2);
00240   }
00241 
00242   template<class VA, class VB, class VC>
00243   forceinline ExecStatus
00244   MultPlusBnd<VA,VB,VC>::post(Home home, VA x0, VB x1, VC x2) {
00245     GECODE_ME_CHECK(x0.gr(home,0));
00246     GECODE_ME_CHECK(x1.gr(home,0));
00247     GECODE_ME_CHECK(x2.gq(home,mll(x0.min(),x1.min())));
00248     GECODE_ME_CHECK(x2.lq(home,mll(x0.max(),x1.max())));
00249     (void) new (home) MultPlusBnd<VA,VB,VC>(home,x0,x1,x2);
00250     return ES_OK;
00251   }
00252 
00253 
00254   /*
00255    * Bounds consistent multiplication
00256    *
00257    */
00258   forceinline
00259   MultBnd::MultBnd(Home home, IntView x0, IntView x1, IntView x2)
00260     : TernaryPropagator<IntView,PC_INT_BND>(home,x0,x1,x2) {}
00261 
00262   forceinline
00263   MultBnd::MultBnd(Space& home, MultBnd& p)
00264     : TernaryPropagator<IntView,PC_INT_BND>(home,p) {}
00265 
00266   /*
00267    * Positive domain consistent multiplication
00268    *
00269    */
00270   template<class View>
00271   forceinline ExecStatus
00272   prop_mult_dom(Space& home, Propagator& p, View x0, View x1, View x2) {
00273     Region r;
00274     SupportValues<View,Region> s0(r,x0), s1(r,x1), s2(r,x2);
00275     while (s0()) {
00276       while (s1()) {
00277         if (s2.support(mll(s0.val(),s1.val()))) {
00278           s0.support(); s1.support();
00279         }
00280         ++s1;
00281       }
00282       s1.reset(); ++s0;
00283     }
00284     GECODE_ME_CHECK(s0.tell(home));
00285     GECODE_ME_CHECK(s1.tell(home));
00286     GECODE_ME_CHECK(s2.tell(home));
00287     return x0.assigned() && x1.assigned() ? home.ES_SUBSUMED(p) : ES_FIX;
00288   }
00289 
00290   template<class VA, class VB, class VC>
00291   forceinline
00292   MultPlusDom<VA,VB,VC>::MultPlusDom(Home home, VA x0, VB x1, VC x2)
00293     : MixTernaryPropagator<VA,PC_INT_DOM,VB,PC_INT_DOM,VC,PC_INT_DOM>
00294   (home,x0,x1,x2) {}
00295 
00296   template<class VA, class VB, class VC>
00297   forceinline
00298   MultPlusDom<VA,VB,VC>::MultPlusDom(Space& home, MultPlusDom<VA,VB,VC>& p)
00299     : MixTernaryPropagator<VA,PC_INT_DOM,VB,PC_INT_DOM,VC,PC_INT_DOM>
00300       (home,p) {}
00301 
00302   template<class VA, class VB, class VC>
00303   Actor*
00304   MultPlusDom<VA,VB,VC>::copy(Space& home) {
00305     return new (home) MultPlusDom<VA,VB,VC>(home,*this);
00306   }
00307 
00308   template<class VA, class VB, class VC>
00309   PropCost
00310   MultPlusDom<VA,VB,VC>::cost(const Space&,
00311                                   const ModEventDelta& med) const {
00312     if (VA::me(med) == ME_INT_DOM)
00313       return PropCost::ternary(PropCost::HI);
00314     else
00315       return PropCost::ternary(PropCost::LO);
00316   }
00317 
00318   template<class VA, class VB, class VC>
00319   ExecStatus
00320   MultPlusDom<VA,VB,VC>::propagate(Space& home, const ModEventDelta& med) {
00321     if (VA::me(med) != ME_INT_DOM) {
00322       GECODE_ES_CHECK((prop_mult_plus_bnd<VA,VB,VC>(home,*this,x0,x1,x2)));
00323       return home.ES_FIX_PARTIAL(*this,VA::med(ME_INT_DOM));
00324     }
00325     IntView y0(x0.varimp()), y1(x1.varimp()), y2(x2.varimp());
00326     return prop_mult_dom<IntView>(home,*this,y0,y1,y2);
00327   }
00328 
00329   template<class VA, class VB, class VC>
00330   forceinline ExecStatus
00331   MultPlusDom<VA,VB,VC>::post(Home home, VA x0, VB x1, VC x2) {
00332     GECODE_ME_CHECK(x0.gr(home,0));
00333     GECODE_ME_CHECK(x1.gr(home,0));
00334     GECODE_ME_CHECK(x2.gq(home,mll(x0.min(),x1.min())));
00335     GECODE_ME_CHECK(x2.lq(home,mll(x0.max(),x1.max())));
00336     (void) new (home) MultPlusDom<VA,VB,VC>(home,x0,x1,x2);
00337     return ES_OK;
00338   }
00339 
00340 
00341   /*
00342    * Domain consistent multiplication
00343    *
00344    */
00345   forceinline
00346   MultDom::MultDom(Home home, IntView x0, IntView x1, IntView x2)
00347     : TernaryPropagator<IntView,PC_INT_DOM>(home,x0,x1,x2) {}
00348 
00349   forceinline
00350   MultDom::MultDom(Space& home, MultDom& p)
00351     : TernaryPropagator<IntView,PC_INT_DOM>(home,p) {}
00352 
00353 }}}
00354 
00355 // STATISTICS: int-prop
00356