tree.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:
 *     http://www.gecode.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining
 *  a copy of this software and associated documentation files (the
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 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
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#include <algorithm>

namespace Gecode { namespace Int { namespace Unary {

  /*
   * Omega tree
   */

  forceinline void
  OmegaNode::init(const OmegaNode&, const OmegaNode&) {
    p = 0; ect = -Limits::infinity;
  }

  forceinline void
  OmegaNode::update(const OmegaNode& l, const OmegaNode& r) {
    p = l.p + r.p;
    ect = std::max(plus(l.ect,r.p), r.ect);
  }

  template<class TaskView>
  forceinline
  OmegaTree<TaskView>::OmegaTree(Region& r, const TaskViewArray<TaskView>& t)
    : TaskTree<TaskView,OmegaNode>(r,t) {
    for (int i=0; i<tasks.size(); i++) {
      leaf(i).p = 0; leaf(i).ect = -Limits::infinity;
    }
    init();
  }

  template<class TaskView>
  forceinline void
  OmegaTree<TaskView>::insert(int i) {
    leaf(i).p = tasks[i].pmin();
    leaf(i).ect = tasks[i].est()+tasks[i].pmin();
    update(i);
  }

  template<class TaskView>
  forceinline void
  OmegaTree<TaskView>::remove(int i) {
    leaf(i).p = 0; leaf(i).ect = -Limits::infinity;
    update(i);
  }

  template<class TaskView>
  forceinline int
  OmegaTree<TaskView>::ect(void) const {
    return root().ect;
  }

  template<class TaskView>
  forceinline int
  OmegaTree<TaskView>::ect(int i) const {
    // Check whether task i is in?
    OmegaTree<TaskView>& o = const_cast<OmegaTree<TaskView>&>(*this);
    if (o.leaf(i).ect != -Limits::infinity) {
      o.remove(i);
      int ect = o.root().ect;
      o.insert(i);
      return ect;
    } else {
      return root().ect;
    }
  }



  /*
   * Omega lambda tree
   */

  forceinline void
  OmegaLambdaNode::init(const OmegaLambdaNode& l, const OmegaLambdaNode& r) {
    OmegaNode::init(l,r);
    lp = p; lect = ect; resEct = undef; resLp = undef;
  }

  forceinline void
  OmegaLambdaNode::update(const OmegaLambdaNode& l, const OmegaLambdaNode& r) {
    OmegaNode::update(l,r);
    if (l.lp + r.p > l.p + r.lp) {
      resLp = l.resLp;
      lp = l.lp + r.p;
    } else {
      resLp = r.resLp;
      lp = l.p + r.lp;
    }
    if ((r.lect >= plus(l.ect,r.lp)) && (r.lect >= plus(l.lect,r.p))) {
      lect = r.lect; resEct = r.resEct;
    } else if (plus(l.ect,r.lp) >= plus(l.lect,r.p)) {
      assert(plus(l.ect,r.lp) > r.lect);
      lect = plus(l.ect,r.lp); resEct = r.resLp;
    } else {
      assert((plus(l.lect,r.p) > r.lect) &&
             (plus(l.lect,r.p) > plus(l.ect,r.lp)));
      lect = plus(l.lect,r.p); resEct = l.resEct;
    }
  }


  template<class TaskView>
  forceinline
  OmegaLambdaTree<TaskView>::OmegaLambdaTree(Region& r,
                                             const TaskViewArray<TaskView>& t,
                                             bool inc)
    : TaskTree<TaskView,OmegaLambdaNode>(r,t) {
    if (inc) {
      // Enter all tasks into tree (omega = all tasks, lambda = empty)
      for (int i=0; i<tasks.size(); i++) {
        leaf(i).p = leaf(i).lp = tasks[i].pmin();
        leaf(i).ect = leaf(i).lect = tasks[i].est()+tasks[i].pmin();
        leaf(i).resEct = OmegaLambdaNode::undef;
        leaf(i).resLp = OmegaLambdaNode::undef;
      }
      update();
    } else {
      // Enter no tasks into tree (omega = empty, lambda = empty)
      for (int i=0; i<tasks.size(); i++) {
        leaf(i).p = leaf(i).lp = 0;
        leaf(i).ect = leaf(i).lect = -Limits::infinity;
        leaf(i).resEct = OmegaLambdaNode::undef;
        leaf(i).resLp = OmegaLambdaNode::undef;
      }
      init();
     }
  }

  template<class TaskView>
  forceinline void
  OmegaLambdaTree<TaskView>::shift(int i) {
    // That means that i is in omega
    assert(leaf(i).ect > -Limits::infinity);
    leaf(i).p = 0;
    leaf(i).ect = -Limits::infinity;
    leaf(i).resEct = i;
    leaf(i).resLp = i;
    update(i);
  }

  template<class TaskView>
  forceinline void
  OmegaLambdaTree<TaskView>::oinsert(int i) {
    leaf(i).p = tasks[i].pmin();
    leaf(i).ect = tasks[i].est()+tasks[i].pmin();
    update(i);
  }

  template<class TaskView>
  forceinline void
  OmegaLambdaTree<TaskView>::linsert(int i) {
    leaf(i).lp = tasks[i].pmin();
    leaf(i).lect = tasks[i].est()+tasks[i].pmin();
    leaf(i).resEct = i;
    leaf(i).resLp = i;
    update(i);
  }

  template<class TaskView>
  forceinline void
  OmegaLambdaTree<TaskView>::lremove(int i) {
    leaf(i).lp = 0;
    leaf(i).lect = -Limits::infinity;
    leaf(i).resEct = OmegaLambdaNode::undef;
    leaf(i).resLp = OmegaLambdaNode::undef;
    update(i);
  }

  template<class TaskView>
  forceinline bool
  OmegaLambdaTree<TaskView>::lempty(void) const {
    return root().resEct < 0;
  }

  template<class TaskView>
  forceinline int
  OmegaLambdaTree<TaskView>::responsible(void) const {
    return root().resEct;
  }

  template<class TaskView>
  forceinline int
  OmegaLambdaTree<TaskView>::ect(void) const {
    return root().ect;
  }

  template<class TaskView>
  forceinline int
  OmegaLambdaTree<TaskView>::lect(void) const {
    return root().lect;
  }

}}}

// STATISTICS: int-prop