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time-tabling.hpp
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1/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
2/*
3 * Main authors:
4 * Christian Schulte <schulte@gecode.org>
5 * Guido Tack <tack@gecode.org>
6 *
7 * Copyright:
8 * Christian Schulte, 2015
9 * Guido Tack, 2010
10 *
11 * This file is part of Gecode, the generic constraint
12 * development environment:
13 * http://www.gecode.org
14 *
15 * Permission is hereby granted, free of charge, to any person obtaining
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20 * permit persons to whom the Software is furnished to do so, subject to
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35
36namespace Gecode { namespace Int { namespace Unary {
37
38 template<class Task>
41 Region r;
42
43 bool assigned;
44 if (Event* e = Event::events(r,t,assigned)) {
45 // Whether resource is free
46 bool free = true;
47 // Set of current but not required tasks
48 Support::BitSet<Region> tasks(r,static_cast<unsigned int>(t.size()));
49
50 // Process events
51 do {
52 // Current time
53 int time = e->time();
54
55 // Process events for completion of required part
56 for ( ; (e->type() == Event::LRT) && (e->time() == time); e++)
57 if (t[e->idx()].mandatory()) {
58 tasks.set(static_cast<unsigned int>(e->idx()));
59 free = true;
60 }
61
62 // Process events for completion of task
63 for ( ; (e->type() == Event::LCT) && (e->time() == time); e++)
64 tasks.clear(static_cast<unsigned int>(e->idx()));
65
66 // Process events for start of task
67 for ( ; (e->type() == Event::EST) && (e->time() == time); e++)
68 tasks.set(static_cast<unsigned int>(e->idx()));
69
70 // Process events for zero-length task
71 for ( ; (e->type() == Event::ZRO) && (e->time() == time); e++)
72 if (!free)
73 return ES_FAILED;
74
75 // Norun start time
76 int nrstime = time;
77 // Process events for start of required part
78 for ( ; (e->type() == Event::ERT) && (e->time() == time); e++)
79 if (t[e->idx()].mandatory()) {
80 tasks.clear(static_cast<unsigned int>(e->idx()));
81 if (!free)
82 return ES_FAILED;
83 free = false;
84 nrstime = time+1;
85 } else if (t[e->idx()].optional() && !free) {
86 GECODE_ME_CHECK(t[e->idx()].excluded(home));
87 }
88
89 if (!free)
91 j(); ++j)
92 // Task j cannot run from time to next time - 1
93 if (t[j.val()].mandatory())
94 GECODE_ME_CHECK(t[j.val()].norun(home, nrstime, e->time() - 1));
95
96 } while (e->type() != Event::END);
97 }
98
99 if (assigned)
100 return home.ES_SUBSUMED(p);
101
102 return ES_NOFIX;
103 }
104
105}}}
106
107// STATISTICS: int-prop
NodeType t
Type of node.
int p
Number of positive literals for node type.
Time-tabling event for task.
Definition task.hh:490
static Event * events(Region &r, const TaskArray< Task > &t, bool &assigned)
Allocate from r and initialize event array with tasks t.
Definition event.hpp:83
@ ZRO
Zero-length task start time.
Definition task.hh:497
@ ERT
Earliest required time of task.
Definition task.hh:498
@ LRT
Latest required time of task.
Definition task.hh:494
@ EST
Earliest start time of task.
Definition task.hh:496
@ END
End marker.
Definition task.hh:499
@ LCT
Latest completion time of task.
Definition task.hh:495
Task array.
Definition task.hh:165
Value iterator for values in a bitset.
Base-class for propagators.
Definition core.hpp:1064
Handle to region.
Definition region.hpp:55
Computation spaces.
Definition core.hpp:1742
void clear(unsigned int i)
Clear bit i.
void set(unsigned int i)
Set bit i.
Simple bitsets.
Definition bitset.hpp:45
ExecStatus ES_SUBSUMED(Propagator &p)
Definition core.hpp:3563
#define GECODE_ME_CHECK(me)
Check whether modification event me is failed, and forward failure.
Definition macros.hpp:52
ExecStatus timetabling(Space &home, Propagator &p, TaskArray< Task > &t)
Perform time-tabling propagation.
Gecode toplevel namespace
Post propagator for SetVar SetOpType SetVar SetRelType r
Definition set.hh:767
ExecStatus
Definition core.hpp:472
@ ES_FAILED
Execution has resulted in failure.
Definition core.hpp:474
@ ES_NOFIX
Propagation has not computed fixpoint.
Definition core.hpp:475