detectable.hpp

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2009
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
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namespace Gecode { namespace Int { namespace Unary {

  template<class ManTaskView>
  forceinline ExecStatus
  detectable(Space& home, TaskViewArray<ManTaskView>& t) {
    sort<ManTaskView,STO_ECT,true>(t);

    Region r;

    OmegaTree<ManTaskView> o(r,t);
    TaskViewIter<ManTaskView,STO_LST,true> q(r,t);
    int* est = r.alloc<int>(t.size());

    for (int i=0; i<t.size(); i++) {
      while (q() && (t[i].ect() > t[q.task()].lst())) {
        o.insert(q.task()); ++q;
      }
      est[i] = o.ect(i);
    }

    for (int i=0; i<t.size(); i++)
      GECODE_ME_CHECK(t[i].est(home,est[i]));

    return ES_OK;
  }

  template<class ManTask>
  ExecStatus
  detectable(Space& home, TaskArray<ManTask>& t) {
    TaskViewArray<typename TaskTraits<ManTask>::TaskViewFwd> f(t);
    GECODE_ES_CHECK(detectable(home,f));
    TaskViewArray<typename TaskTraits<ManTask>::TaskViewBwd> b(t);
    return detectable(home,b);
  }


  template<class OptTaskView, class PL>
  forceinline ExecStatus
  detectable(Space& home, Propagator& p, TaskViewArray<OptTaskView>& t) {
    sort<OptTaskView,STO_ECT,true>(t);

    Region r;

    OmegaTree<OptTaskView> o(r,t);
    ManTaskViewIter<OptTaskView,STO_LST,true> q(r,t);
    int* est = r.alloc<int>(t.size());

    for (int i=0; i<t.size(); i++) {
      while (q() && (t[i].ect() > t[q.task()].lst())) {
        o.insert(q.task()); ++q;
      }
      est[i] = o.ect(i);
    }

    int n = t.size();
    for (int i=n; i--; )
      if (t[i].mandatory()) {
        GECODE_ME_CHECK(t[i].est(home,est[i]));
      } else if (est[i] > t[i].lst()) {
        GECODE_ME_CHECK(t[i].excluded(home));
        t[i].cancel(home,p,PL::pc); t[i]=t[--n];
      }
    t.size(n);

    return (t.size() < 2) ? home.ES_SUBSUMED(p) : ES_OK;
  }

  template<class OptTask, class PL>
  ExecStatus
  detectable(Space& home, Propagator& p, TaskArray<OptTask>& t) {
    TaskViewArray<typename TaskTraits<OptTask>::TaskViewFwd> f(t);
    GECODE_ES_CHECK((detectable<typename TaskTraits<OptTask>::TaskViewFwd,PL>
                     (home,p,f)));
    TaskViewArray<typename TaskTraits<OptTask>::TaskViewBwd> b(t);
    return detectable<typename TaskTraits<OptTask>::TaskViewBwd,PL>
      (home,p,b);
  }

}}}

// STATISTICS: int-prop