basic.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 * Guido Tack <tack@gecode.org> 00006 * 00007 * Copyright: 00008 * Christian Schulte, 2010 00009 * Guido Tack, 2010 00010 * 00011 * Last modified: 00012 * $Date: 2011-01-18 23:37:08 +0100 (Tue, 18 Jan 2011) $ by $Author: tack $ 00013 * $Revision: 11551 $ 00014 * 00015 * This file is part of Gecode, the generic constraint 00016 * development environment: 00017 * http://www.gecode.org 00018 * 00019 * Permission is hereby granted, free of charge, to any person obtaining 00020 * a copy of this software and associated documentation files (the 00021 * "Software"), to deal in the Software without restriction, including 00022 * without limitation the rights to use, copy, modify, merge, publish, 00023 * distribute, sublicense, and/or sell copies of the Software, and to 00024 * permit persons to whom the Software is furnished to do so, subject to 00025 * the following conditions: 00026 * 00027 * The above copyright notice and this permission notice shall be 00028 * included in all copies or substantial portions of the Software. 00029 * 00030 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 00031 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 00032 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 00033 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 00034 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 00035 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 00036 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 00037 * 00038 */ 00039 00040 namespace Gecode { namespace Scheduling { namespace Cumulative { 00041 00043 class Event { 00044 public: 00046 enum Type { 00047 LRT = 0, 00048 LCT = 1, 00049 EST = 2, 00050 ZRO = 3, 00051 ERT = 4, 00052 END = 5 00053 }; 00054 Type e; 00055 int t; 00056 int i; 00057 00058 void init(Type e, int t, int i); 00060 bool operator <(const Event& e) const; 00061 }; 00062 00064 template<class Task> 00065 class TaskByDecCap { 00066 public: 00068 bool operator ()(const Task& t1, const Task& t2) const; 00069 }; 00070 00071 forceinline void 00072 Event::init(Event::Type e0, int t0, int i0) { 00073 e=e0; t=t0; i=i0; 00074 } 00075 00076 forceinline bool 00077 Event::operator <(const Event& e) const { 00078 if (this->t == e.t) 00079 return this->e < e.e; 00080 return this->t < e.t; 00081 } 00082 00083 template<class Task> 00084 forceinline bool 00085 TaskByDecCap<Task>::operator ()(const Task& t1, const Task& t2) const { 00086 return t1.c() > t2.c(); 00087 } 00088 00089 00090 // Basic propagation 00091 template<class Task> 00092 ExecStatus 00093 basic(Space& home, Propagator& p, int c, TaskArray<Task>& t) { 00094 // Sort tasks by decreasing capacity 00095 TaskByDecCap<Task> tbdc; 00096 Support::quicksort(&t[0], t.size(), tbdc); 00097 00098 Region r(home); 00099 00100 Event* e = r.alloc<Event>(4*t.size()+1); 00101 00102 // Initialize events 00103 bool assigned=true; 00104 { 00105 bool required=false; 00106 int n=0; 00107 for (int i=t.size(); i--; ) 00108 if (t[i].assigned()) { 00109 // Only add required part 00110 if (t[i].pmin() > 0) { 00111 required = true; 00112 e[n++].init(Event::ERT,t[i].lst(),i); 00113 e[n++].init(Event::LRT,t[i].ect(),i); 00114 } else if (t[i].pmax() == 0) { 00115 required = true; 00116 e[n++].init(Event::ZRO,t[i].lst(),i); 00117 } 00118 } else { 00119 assigned = false; 00120 e[n++].init(Event::EST,t[i].est(),i); 00121 e[n++].init(Event::LCT,t[i].lct(),i); 00122 // Check whether task has required part 00123 if (t[i].lst() < t[i].ect()) { 00124 required = true; 00125 e[n++].init(Event::ERT,t[i].lst(),i); 00126 e[n++].init(Event::LRT,t[i].ect(),i); 00127 } 00128 } 00129 00130 // Check whether no task has a required part 00131 if (!required) 00132 return assigned ? home.ES_SUBSUMED(p) : ES_FIX; 00133 00134 // Write end marker 00135 e[n++].init(Event::END,Int::Limits::infinity,-1); 00136 00137 // Sort events 00138 Support::quicksort(e, n); 00139 } 00140 00141 // Set of current but not required tasks 00142 Support::BitSet<Region> tasks(r,static_cast<unsigned int>(t.size())); 00143 00144 // Process events, use c as the capacity that is still free 00145 while (e->e != Event::END) { 00146 // Current time 00147 int time = e->t; 00148 00149 // Process events for completion of required part 00150 for ( ; (e->t == time) && (e->e == Event::LRT); e++) 00151 if (t[e->i].mandatory()) { 00152 tasks.set(static_cast<unsigned int>(e->i)); c += t[e->i].c(); 00153 } 00154 // Process events for completion of task 00155 for ( ; (e->t == time) && (e->e == Event::LCT); e++) 00156 tasks.clear(static_cast<unsigned int>(e->i)); 00157 // Process events for start of task 00158 for ( ; (e->t == time) && (e->e == Event::EST); e++) 00159 tasks.set(static_cast<unsigned int>(e->i)); 00160 // Process events for zero-length task 00161 for ( ; (e->t == time) && (e->e == Event::ZRO); e++) 00162 if (c < t[e->i].c()) 00163 return ES_FAILED; 00164 00165 // norun start time for 0-length tasks 00166 int zltime = time; 00167 // Process events for start of required part 00168 for ( ; (e->t == time) && (e->e == Event::ERT); e++) 00169 if (t[e->i].mandatory()) { 00170 tasks.clear(static_cast<unsigned int>(e->i)); 00171 c -= t[e->i].c(); zltime = time+1; 00172 if (c < 0) 00173 return ES_FAILED; 00174 } else if (t[e->i].optional() && (t[e->i].c() > c)) { 00175 GECODE_ME_CHECK(t[e->i].excluded(home)); 00176 } 00177 00178 // Exploit that tasks are sorted according to capacity 00179 for (Iter::Values::BitSet<Support::BitSet<Region> > j(tasks); 00180 j() && (t[j.val()].c() > c); ++j) 00181 // Task j cannot run from time to next time - 1 00182 if (t[j.val()].mandatory()) { 00183 if (t[j.val()].pmin() > 0) { 00184 GECODE_ME_CHECK(t[j.val()].norun(home, time, e->t - 1)); 00185 } else { 00186 GECODE_ME_CHECK(t[j.val()].norun(home, zltime, e->t - 1)); 00187 } 00188 } 00189 } 00190 00191 return assigned ? home.ES_SUBSUMED(p) : ES_NOFIX; 00192 } 00193 00194 }}} 00195 00196 // STATISTICS: scheduling-prop