1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/********************* */
/*! \file justification_heuristic.h
** \verbatim
** Top contributors (to current version):
** Kshitij Bansal, Paul Meng, Tim King
** This file is part of the CVC4 project.
** Copyright (c) 2009-2017 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief Justification heuristic for decision making
**
** A ATGP-inspired justification-based decision heuristic. See
** [insert reference] for more details. This code is, or not, based
** on the CVC3 implementation of the same heuristic.
**
** It needs access to the simplified but non-clausal formula.
**/
#include "cvc4_private.h"
#ifndef __CVC4__DECISION__JUSTIFICATION_HEURISTIC
#define __CVC4__DECISION__JUSTIFICATION_HEURISTIC
#include <unordered_set>
#include "context/cdhashmap.h"
#include "context/cdhashset.h"
#include "context/cdlist.h"
#include "decision/decision_attributes.h"
#include "decision/decision_engine.h"
#include "decision/decision_strategy.h"
#include "expr/node.h"
#include "prop/sat_solver_types.h"
namespace CVC4 {
namespace decision {
class JustificationHeuristic : public ITEDecisionStrategy {
// TRUE FALSE MEH
enum SearchResult {FOUND_SPLITTER, NO_SPLITTER, DONT_KNOW};
typedef std::vector<pair<TNode,TNode> > IteList;
typedef context::CDHashMap<TNode,IteList,TNodeHashFunction> IteCache;
typedef std::vector<TNode> ChildList;
typedef context::CDHashMap<TNode,pair<ChildList,ChildList>,TNodeHashFunction> ChildCache;
typedef context::CDHashMap<TNode,TNode,TNodeHashFunction> SkolemMap;
typedef context::CDHashMap<TNode,pair<DecisionWeight,DecisionWeight>,TNodeHashFunction> WeightCache;
// being 'justified' is monotonic with respect to decisions
typedef context::CDHashSet<Node,NodeHashFunction> JustifiedSet;
JustifiedSet d_justified;
typedef context::CDHashMap<Node,DecisionWeight,NodeHashFunction> ExploredThreshold;
ExploredThreshold d_exploredThreshold;
context::CDO<unsigned> d_prvsIndex;
context::CDO<unsigned> d_threshPrvsIndex;
IntStat d_helfulness;
IntStat d_giveup;
TimerStat d_timestat;
/**
* A copy of the assertions that need to be justified
* directly. Doesn't have ones introduced during during ITE-removal.
*/
context::CDList<TNode> d_assertions;
//TNode is fine since decisionEngine has them too
/** map from ite-rewrite skolem to a boolean-ite assertion */
SkolemMap d_iteAssertions;
// 'key' being TNode is fine since if a skolem didn't exist anywhere,
// we won't look it up. as for 'value', same reason as d_assertions
/** Cache for ITE skolems present in a atomic formula */
IteCache d_iteCache;
/**
* This is used to prevent infinite loop when trying to find a
* splitter. Can happen when exploring assertion corresponding to a
* term-ITE.
*/
std::unordered_set<TNode,TNodeHashFunction> d_visited;
/**
* Set to track visited nodes in a dfs search done in computeITE
* function
*/
std::unordered_set<TNode,TNodeHashFunction> d_visitedComputeITE;
/** current decision for the recursive call */
SatLiteral d_curDecision;
/** current threshold for the recursive call */
DecisionWeight d_curThreshold;
/** child cache */
ChildCache d_childCache;
/** computed polarized weight cache */
WeightCache d_weightCache;
class myCompareClass {
JustificationHeuristic* d_jh;
bool d_b;
public:
myCompareClass(JustificationHeuristic* jh, bool b):d_jh(jh),d_b(b) {};
bool operator() (TNode n1, TNode n2) {
return d_jh->getWeightPolarized(n1, d_b) < d_jh->getWeightPolarized(n2, d_b);
}
};
public:
JustificationHeuristic(CVC4::DecisionEngine* de,
context::UserContext *uc,
context::Context *c);
~JustificationHeuristic();
prop::SatLiteral getNext(bool &stopSearch) override;
void addAssertions(const std::vector<Node> &assertions,
unsigned assertionsEnd,
IteSkolemMap iteSkolemMap) override;
private:
/* getNext with an option to specify threshold */
prop::SatLiteral getNextThresh(bool &stopSearch, DecisionWeight threshold);
SatLiteral findSplitter(TNode node, SatValue desiredVal);
/**
* Do all the hard work.
*/
SearchResult findSplitterRec(TNode node, SatValue value);
/* Helper functions */
void setJustified(TNode);
bool checkJustified(TNode);
DecisionWeight getExploredThreshold(TNode);
void setExploredThreshold(TNode);
void setPrvsIndex(int);
int getPrvsIndex();
DecisionWeight getWeightPolarized(TNode n, bool polarity);
DecisionWeight getWeightPolarized(TNode n, SatValue);
static DecisionWeight getWeight(TNode);
bool compareByWeightFalse(TNode, TNode);
bool compareByWeightTrue(TNode, TNode);
TNode getChildByWeight(TNode n, int i, bool polarity);
/* If literal exists corresponding to the node return
that. Otherwise an UNKNOWN */
SatValue tryGetSatValue(Node n);
/* Get list of all term-ITEs for the atomic formula v */
JustificationHeuristic::IteList getITEs(TNode n);
/**
* For big and/or nodes, a cache to save starting index into children
* for efficiently.
*/
typedef context::CDHashMap<TNode, int, TNodeHashFunction> StartIndexCache;
StartIndexCache d_startIndexCache;
int getStartIndex(TNode node);
void saveStartIndex(TNode node, int val);
/* Compute all term-ITEs in a node recursively */
void computeITEs(TNode n, IteList &l);
SearchResult handleAndOrEasy(TNode node, SatValue desiredVal);
SearchResult handleAndOrHard(TNode node, SatValue desiredVal);
SearchResult handleBinaryEasy(TNode node1, SatValue desiredVal1,
TNode node2, SatValue desiredVal2);
SearchResult handleBinaryHard(TNode node1, SatValue desiredVal1,
TNode node2, SatValue desiredVal2);
SearchResult handleITE(TNode node, SatValue desiredVal);
SearchResult handleEmbeddedITEs(TNode node);
};/* class JustificationHeuristic */
}/* namespace decision */
}/* namespace CVC4 */
#endif /* __CVC4__DECISION__JUSTIFICATION_HEURISTIC */
|
