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
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/********************* */
/*! \file partial_model.h
** \verbatim
** Original author: taking
** Major contributors: none
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief [[ Add one-line brief description here ]]
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#include "context/context.h"
#include "context/cdmap.h"
#include "theory/arith/delta_rational.h"
#include "expr/attribute.h"
#include "expr/node.h"
#include <deque>
#ifndef __CVC4__THEORY__ARITH__PARTIAL_MODEL_H
#define __CVC4__THEORY__ARITH__PARTIAL_MODEL_H
namespace CVC4 {
namespace theory {
namespace arith {
namespace partial_model {
struct DeltaRationalCleanupStrategy{
static void cleanup(DeltaRational* dq){
Debug("arithgc") << "cleaning up " << dq << "\n";
if(dq != NULL){
delete dq;
}
}
};
struct AssignmentAttrID {};
typedef expr::Attribute<AssignmentAttrID,
DeltaRational*,
DeltaRationalCleanupStrategy> Assignment;
struct SafeAssignmentAttrID {};
typedef expr::Attribute<SafeAssignmentAttrID,
DeltaRational*,
DeltaRationalCleanupStrategy> SafeAssignment;
/**
* This defines a context dependent delta rational map.
* This is used to keep track of the current lower and upper bounds on
* each variable. This information is conext dependent.
*/
typedef context::CDMap<TNode, DeltaRational, TNodeHashFunction> CDDRationalMap;
/* Side disucssion for why new tables are introduced instead of using the attribute
* framework.
* It comes down to that the obvious ways to use the current attribute framework do
* do not provide a terribly satisfying answer.
* - Suppose the type of the attribute is CD and maps to type DeltaRational.
* Well it can't map to a DeltaRational, and it thus it will be a DeltaRational*
* However being context dependent means givening up cleanup functions.
* So this leaks memory.
* - Suppose the type of the attribute is CD and the type mapped to
* was a Node wrapping a CONST_DELTA_RATIONAL.
* This was rejected for inefficiency, and uglyness.
* Inefficiency: Every lookup and comparison will require going through the
* massaging in between a node and the constant being wrapped. Every update
* requires going through the additional expense of creating at least 1 node.
* The Uglyness: If this was chosen it would also suggest using comparisons against
* DeltaRationals for the tracking the constraints for conflict analysis.
* This seems to invite misuse and introducing Nodes that should probably not escape
* arith.
* - Suppose that the of the attribute was not CD and mapped to a CDO<DeltaRational*>
* or similarly a ContextObj that wraps a DeltaRational*.
* This is currently rejected just because this is difficult to get right,
* and maintain. However with enough effort this the best solution is probably of
* this form.
*/
/**
* This is the literal that was asserted in the current context to the theory
* that asserted the tightest lower bound on a variable.
* For example: for a variable x this could be the constraint (>= x 4) or (not (<= x 50))
* Note the strong correspondence between this and LowerBoundMap.
* This is used during conflict analysis.
*/
struct LowerConstraintAttrID {};
typedef expr::CDAttribute<LowerConstraintAttrID,TNode> LowerConstraint;
/**
* See the documentation for LowerConstraint.
*/
struct UpperConstraintAttrID {};
typedef expr::CDAttribute<UpperConstraintAttrID,TNode> UpperConstraint;
}; /*namespace partial_model*/
struct TheoryArithPropagatedID {};
typedef expr::CDAttribute<TheoryArithPropagatedID, bool> TheoryArithPropagated;
class ArithPartialModel {
private:
partial_model::CDDRationalMap d_LowerBoundMap;
partial_model::CDDRationalMap d_UpperBoundMap;
typedef std::vector<TNode> HistoryList;
HistoryList d_history;
bool d_unsafeMode;
public:
ArithPartialModel(context::Context* c):
d_LowerBoundMap(c),
d_UpperBoundMap(c),
d_history(),
d_unsafeMode(false)
{ }
void setLowerConstraint(TNode x, TNode constraint);
void setUpperConstraint(TNode x, TNode constraint);
TNode getLowerConstraint(TNode x);
TNode getUpperConstraint(TNode x);
void initialize(TNode x, const DeltaRational& r);
DeltaRational getSafeAssignment(TNode x) const;
bool isInUnsafeMode() { return d_unsafeMode; }
void turnOnUnsafeMode();
void turnOffUnsafeMode();
void revertAssignmentChanges();
void commitAssignmentChanges();
void setUpperBound(TNode x, const DeltaRational& r);
void setLowerBound(TNode x, const DeltaRational& r);
void setAssignment(TNode x, const DeltaRational& r);
/** Must know that the bound exists before calling this! */
DeltaRational getUpperBound(TNode x) const;
DeltaRational getLowerBound(TNode x) const;
const DeltaRational& getAssignment(TNode x) const;
/**
* x <= l
* ? c < l
*/
bool belowLowerBound(TNode x, const DeltaRational& c, bool strict);
/**
* x <= u
* ? c < u
*/
bool aboveUpperBound(TNode x, const DeltaRational& c, bool strict);
bool strictlyBelowUpperBound(TNode x);
bool strictlyAboveLowerBound(TNode x);
bool assignmentIsConsistent(TNode x);
void printModel(TNode x);
private:
void clearSafeAssignments(bool revert);
};
}; /* namesapce arith */
}; /* namespace theory */
}; /* namespace CVC4 */
#endif /* __CVC4__THEORY__ARITH__PARTIAL_MODEL_H */
|
