Beispiel #1
0
  ExecStatus
  ElementUnion<SView,RView>::propagate(Space& home, const ModEventDelta&) {
    Region r(home);
    int n = iv.size();

    bool loopVar;
    do {
      loopVar = false;

      // Cache the upper bound iterator, as we have to
      // modify the upper bound while iterating
      LubRanges<RView> x1ub(x1);
      Iter::Ranges::Cache<LubRanges<RView> > x1ubc(r,x1ub);
      Iter::Ranges::ToValues<Iter::Ranges::Cache<LubRanges<RView> > >
        vx1ub(x1ubc);

      GlbRanges<RView> x1lb(x1);
      Iter::Ranges::Cache<GlbRanges<RView> > x1lbc(r,x1lb);
      Iter::Ranges::ToValues<Iter::Ranges::Cache<GlbRanges<RView> > >
        vx1(x1lbc);

      // In the first iteration, compute in before[i] the union
      // of all the upper bounds of the x_i. At the same time,
      // exclude inconsistent x_i from x1 and remove them from
      // the list, cancel their dependencies.

      GLBndSet sofarBefore(home);
      LUBndSet selectedInter(home, IntSet (Limits::min,
                                   Limits::max));
      GLBndSet* before =
        static_cast<GLBndSet*>(r.ralloc(sizeof(GLBndSet)*n));

      int j = 0;
      int i = 0;

      unsigned int maxCard = 0;
      unsigned int minCard = Limits::card;

      while ( vx1ub() ) {

        // Remove vars at indices not in the upper bound
        if (iv[i].idx < vx1ub.val()) {
          iv[i].view.cancel(home,*this, PC_SET_ANY);
          ++i;
          continue;
        }
        assert(iv[i].idx == vx1ub.val());
        iv[j] = iv[i];

        SView candidate = iv[j].view;
        int candidateInd = iv[j].idx;

        // inter = glb(candidate) & complement(lub(x0))
        GlbRanges<SView> candlb(candidate);
        LubRanges<SView> x0ub(x0);
        Iter::Ranges::Diff<GlbRanges<SView>,
          LubRanges<SView> > diff(candlb, x0ub);

        bool selectSingleInconsistent = false;
        if (x1.cardMax() <= 1) {
          GlbRanges<SView> x0lb(x0);
          LubRanges<SView> candub(candidate);
          Iter::Ranges::Diff<GlbRanges<SView>,
                             LubRanges<SView> > diff2(x0lb, candub);
          selectSingleInconsistent = diff2() || candidate.cardMax() < x0.cardMin();
        }

        // exclude inconsistent x_i
        // an x_i is inconsistent if
        //  * at most one x_i can be selected and there are
        //    elements in x_0 that can't be in x_i
        //    (selectSingleInconsistent)
        //  * its min cardinality is greater than maxCard of x0
        //  * inter is not empty (there are elements in x_i
        //    that can't be in x_0)
        if (selectSingleInconsistent ||
            candidate.cardMin() > x0.cardMax() ||
            diff()) {
          ModEvent me = (x1.exclude(home,candidateInd));
          loopVar |= me_modified(me);
          GECODE_ME_CHECK(me);

          iv[j].view.cancel(home,*this, PC_SET_ANY);
          ++i;
          ++vx1ub;
          continue;
        } else {
          // if x_i is consistent, check whether we know
          // that its index is in x1
          if (vx1() && vx1.val()==candidateInd) {
            // x0 >= candidate, candidate <= x0
            GlbRanges<SView> candlb(candidate);
            ModEvent me = x0.includeI(home,candlb);
            loopVar |= me_modified(me);
            GECODE_ME_CHECK(me);

            LubRanges<SView> x0ub(x0);
            me = candidate.intersectI(home,x0ub);
            loopVar |= me_modified(me);
            GECODE_ME_CHECK(me);
            ++vx1;
          }
          new (&before[j]) GLBndSet(home);
          before[j].update(home,sofarBefore);
          LubRanges<SView> cub(candidate);
          sofarBefore.includeI(home,cub);
          GlbRanges<SView> clb(candidate);
          selectedInter.intersectI(home,clb);
          maxCard = std::max(maxCard, candidate.cardMax());
          minCard = std::min(minCard, candidate.cardMin());
        }

        ++vx1ub;
        ++i; ++j;
      }

      // cancel the variables with index greater than
      // max of lub(x1)
      for (int k=i; k<n; k++) {
        iv[k].view.cancel(home,*this, PC_SET_ANY);
      }
      n = j;
      iv.size(n);

      if (x1.cardMax()==0) {
        // Selector is empty, hence the result must be empty
        {
          GECODE_ME_CHECK(x0.cardMax(home,0));
        }
        for (int i=n; i--;)
          before[i].dispose(home);
        return home.ES_SUBSUMED(*this);
      }

      if (x1.cardMin() > 0) {
        // Selector is not empty, hence the intersection of the
        // possibly selected lower bounds is contained in x0
        BndSetRanges si(selectedInter);
        ModEvent me = x0.includeI(home, si);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
        me = x0.cardMin(home, minCard);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
      }
      selectedInter.dispose(home);

      if (x1.cardMax() <= 1) {
        ModEvent me = x0.cardMax(home, maxCard);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
      }

      {
        // x0 <= sofarBefore
        BndSetRanges sfB(sofarBefore);
        ModEvent me = x0.intersectI(home,sfB);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
      }

      sofarBefore.dispose(home);

      GLBndSet sofarAfter(home);

      // In the second iteration, this time backwards, compute
      // sofarAfter as the union of all lub(x_j) with j>i
      for (int i=n; i--;) {
        // TODO: check for size of universe here?
        // if (sofarAfter.size() == 0) break;

        // extra = inter(before[i], sofarAfter) - lub(x0)
        BndSetRanges b(before[i]);
        BndSetRanges s(sofarAfter);
        GlbRanges<SView> x0lb(x0);
        Iter::Ranges::Union<BndSetRanges, BndSetRanges> inter(b,s);
        Iter::Ranges::Diff<GlbRanges<SView>,
          Iter::Ranges::Union<BndSetRanges,BndSetRanges> > diff(x0lb, inter);
        if (diff()) {
          ModEvent me = (x1.include(home,iv[i].idx));
          loopVar |= me_modified(me);
          GECODE_ME_CHECK(me);

          // candidate != extra
          me = iv[i].view.includeI(home,diff);
          loopVar |= me_modified(me);
          GECODE_ME_CHECK(me);
        }

        LubRanges<SView> iviub(iv[i].view);
        sofarAfter.includeI(home,iviub);
        before[i].dispose(home);
      }
      sofarAfter.dispose(home);

    } while (loopVar);

    // Test whether we determined x1 without determining x0
    if (x1.assigned() && !x0.assigned()) {
      int ubsize = static_cast<int>(x1.lubSize());
      if (ubsize > 2) {
        assert(ubsize==n);
        ViewArray<SView> is(home,ubsize);
        for (int i=n; i--;)
          is[i]=iv[i].view;
        GECODE_REWRITE(*this,(RelOp::UnionN<SView, SView>
                        ::post(home(*this),is,x0)));
      } else if (ubsize == 2) {
        assert(n==2);
        SView a = iv[0].view;
        SView b = iv[1].view;
        GECODE_REWRITE(*this,(RelOp::Union<SView, SView, SView>
                       ::post(home(*this),a,b,x0)));
      } else if (ubsize == 1) {
        assert(n==1);
        GECODE_REWRITE(*this,(Rel::Eq<SView,SView>::post(home(*this),x0,iv[0].view)));
      } else {
        GECODE_ME_CHECK(x0.cardMax(home, 0));
        return home.ES_SUBSUMED(*this);
      }
    }

    bool allAssigned = true;
    for (int i=iv.size(); i--;) {
      if (!iv[i].view.assigned()) {
        allAssigned = false;
        break;
      }
    }
    if (x0.assigned() && x1.assigned() && allAssigned) {
      return home.ES_SUBSUMED(*this);
    }

    return ES_FIX;
  }
Beispiel #2
0
  ExecStatus
  ElementUnionConst<SView,RView>::propagate(Space& home, const ModEventDelta&) {
    Region r(home);

    bool* stillSelected = r.alloc<bool>(n_iv);

    bool loopVar;
    do {
      loopVar = false;
      for (int i=n_iv; i--;)
        stillSelected[i] = false;

      // Cache the upper bound iterator, as we have to
      // modify the upper bound while iterating
      LubRanges<RView> x1ub(x1);
      Iter::Ranges::Cache x1ubc(r,x1ub);
      Iter::Ranges::ToValues<Iter::Ranges::Cache>
        vx1ub(x1ubc);

      GlbRanges<RView> x1lb(x1);
      Iter::Ranges::Cache x1lbc(r,x1lb);
      Iter::Ranges::ToValues<Iter::Ranges::Cache>
        vx1(x1lbc);

      // In the first iteration, compute in before[i] the union
      // of all the upper bounds of the x_i. At the same time,
      // exclude inconsistent x_i from x1.

      GLBndSet sofarBefore(home);
      LUBndSet selectedInter(home, IntSet (Limits::min,
                                   Limits::max));
      GLBndSet* before =
        static_cast<GLBndSet*>(r.ralloc(sizeof(GLBndSet)*n_iv));

      unsigned int maxCard = 0;
      unsigned int minCard = Limits::card;

      while (vx1ub()) {
        int i = vx1ub.val();

        IntSetRanges candCardR(iv[i]);
        unsigned int candidateCard = Iter::Ranges::size(candCardR);

        IntSetRanges candlb(iv[i]);
        LubRanges<SView> x0ub(x0);
        Iter::Ranges::Diff<IntSetRanges,
          LubRanges<SView> > diff(candlb, x0ub);

        bool selectSingleInconsistent = false;
        if (x1.cardMax() <= 1) {
          GlbRanges<SView> x0lb(x0);
          IntSetRanges candub(iv[i]);
          Iter::Ranges::Diff<GlbRanges<SView>,
                             IntSetRanges > diff2(x0lb, candub);
          selectSingleInconsistent = diff2() || candidateCard < x0.cardMin();
        }

        // exclude inconsistent x_i
        // an x_i is inconsistent if
        //  * at most one x_i can be selected and there are
        //    elements in x_0 that can't be in x_i
        //    (selectSingleInconsistent)
        //  * its min cardinality is greater than maxCard of x0
        //  * inter is not empty (there are elements in x_i
        //    that can't be in x_0)
        if (selectSingleInconsistent ||
            candidateCard > x0.cardMax() ||
            diff()) {
          ModEvent me = (x1.exclude(home,i));
          loopVar |= me_modified(me);
          GECODE_ME_CHECK(me);
        } else {
          stillSelected[i] = true;
          // if x_i is consistent, check whether we know
          // that its index is in x1
          if (vx1() && vx1.val()==i) {
            // x0 >= candidate, candidate <= x0
            // GlbRanges<SView> candlb(candidate);
            IntSetRanges candlb(iv[i]);
            ModEvent me = x0.includeI(home,candlb);
            loopVar |= me_modified(me);
            GECODE_ME_CHECK(me);
            ++vx1;
          }
          new (&before[i]) GLBndSet(home);
          before[i].update(home,sofarBefore);
          IntSetRanges cub(iv[i]);
          sofarBefore.includeI(home,cub);
          IntSetRanges clb(iv[i]);
          selectedInter.intersectI(home,clb);
          maxCard = std::max(maxCard, candidateCard);
          minCard = std::min(minCard, candidateCard);
        }

        ++vx1ub;
      }

      if (x1.cardMax()==0) {
        // Selector is empty, hence the result must be empty
        {
          GECODE_ME_CHECK(x0.cardMax(home,0));
        }
        for (int i=n_iv; i--;)
          if (stillSelected[i])
            before[i].dispose(home);
        selectedInter.dispose(home);
        sofarBefore.dispose(home);
        return home.ES_SUBSUMED(*this);
      }

      if (x1.cardMin() > 0) {
        // Selector is not empty, hence the intersection of the
        // possibly selected lower bounds is contained in x0
        BndSetRanges si(selectedInter);
        ModEvent me = x0.includeI(home, si);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
        me = x0.cardMin(home, minCard);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
      }
      selectedInter.dispose(home);

      if (x1.cardMax() <= 1) {
        ModEvent me = x0.cardMax(home, maxCard);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
      }

      {
        // x0 <= sofarBefore
        BndSetRanges sfB(sofarBefore);
        ModEvent me = x0.intersectI(home,sfB);
        loopVar |= me_modified(me);
        GECODE_ME_CHECK(me);
      }

      sofarBefore.dispose(home);

      GLBndSet sofarAfter(home);

      // In the second iteration, this time backwards, compute
      // sofarAfter as the union of all lub(x_j) with j>i
      for (int i=n_iv; i--;) {
        if (!stillSelected[i])
          continue;
        BndSetRanges b(before[i]);
        BndSetRanges s(sofarAfter);
        GlbRanges<SView> x0lb(x0);
        Iter::Ranges::Union<BndSetRanges, BndSetRanges> inter(b,s);
        Iter::Ranges::Diff<GlbRanges<SView>,
          Iter::Ranges::Union<BndSetRanges,BndSetRanges> > diff(x0lb, inter);
        if (diff()) {
          ModEvent me = (x1.include(home,i));
          loopVar |= me_modified(me);
          GECODE_ME_CHECK(me);

          // candidate != extra
          IntSetRanges ivi(iv[i]);
          if (!Iter::Ranges::subset(diff, ivi))
            GECODE_ME_CHECK(ME_SET_FAILED);
        }

        IntSetRanges iviub(iv[i]);
        sofarAfter.includeI(home,iviub);
        before[i].dispose(home);
      }
      sofarAfter.dispose(home);

    } while (loopVar);

    if (x1.assigned()) {
      assert(x0.assigned());
      return home.ES_SUBSUMED(*this);
    }

    return ES_FIX;
  }