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
|
/******************************************************************************
* Top contributors (to current version):
* Gereon Kremer
*
* This file is part of the cvc5 project.
*
* Copyright (c) 2009-2021 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.
* ****************************************************************************
*
* Extract bounds on variables from theory atoms.
*/
#ifndef CVC5__THEORY__ARITH__BOUND_INFERENCE_H
#define CVC5__THEORY__ARITH__BOUND_INFERENCE_H
#include <map>
#include <utility>
#include <vector>
#include "expr/node.h"
namespace cvc5 {
namespace theory {
namespace arith {
struct Bounds
{
/** The lower bound value */
Node lower_value;
/** Whether the lower bound is strict or weak */
bool lower_strict = true;
/** The lower bound as constraint */
Node lower_bound;
/** The origin of the lower bound */
Node lower_origin;
/** The upper bound value */
Node upper_value;
/** Whether the upper bound is strict or weak */
bool upper_strict = true;
/** The upper bound as constraint */
Node upper_bound;
/** The origin of the upper bound */
Node upper_origin;
};
/** Print the current bounds. */
std::ostream& operator<<(std::ostream& os, const Bounds& b);
/**
* A utility class that extracts direct bounds on arithmetic terms from theory
* atoms.
*/
class BoundInference
{
public:
void reset();
/**
* Get the current interval for lhs. Creates a new (full) interval if
* necessary.
*/
Bounds& get_or_add(const Node& lhs);
/**
* Get the current interval for lhs. Returns a full interval if no interval
* was derived yet.
*/
Bounds get(const Node& lhs) const;
/** Return the current term bounds as an interval assignment. */
const std::map<Node, Bounds>& get() const;
/**
* Add a new theory atom. Return true if the theory atom induces a new
* term bound.
* If onlyVariables is true, the left hand side needs to be a single
* variable to induce a bound.
*/
bool add(const Node& n, bool onlyVariables = true);
/**
* Post-processes a set of nodes and replaces bounds by their origins.
* This utility sometimes creates new bounds, either due to tightening of
* integer terms or because an equality was derived from two weak
* inequalities. While the origins of these new bounds are recorded in
* lower_origin and upper_origin, this method can be used to conveniently
* replace these new nodes by their origins.
* This can be used, for example, when constructing conflicts.
*/
void replaceByOrigins(std::vector<Node>& nodes) const;
private:
/** The currently strictest bounds for every lhs. */
std::map<Node, Bounds> d_bounds;
/** Updates the lower bound for the given lhs */
void update_lower_bound(const Node& origin,
const Node& lhs,
const Node& value,
bool strict);
/** Updates the upper bound for the given lhs */
void update_upper_bound(const Node& origin,
const Node& lhs,
const Node& value,
bool strict);
};
/** Print the current variable bounds. */
std::ostream& operator<<(std::ostream& os, const BoundInference& bi);
std::map<Node, std::pair<Node,Node>> getBounds(const std::vector<Node>& assertions);
} // namespace arith
} // namespace theory
} // namespace cvc5
#endif
|
