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
|
/********************* */
/*! \file substitutions.cpp
** \verbatim
** Original author: dejan
** Major contributors: none
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010, 2011 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 A substitution mapping for theory simplification
**
** A substitution mapping for theory simplification.
**/
#include "theory/substitutions.h"
using namespace std;
namespace CVC4 {
namespace theory {
struct substitution_stack_element {
TNode node;
bool children_added;
substitution_stack_element(TNode node)
: node(node), children_added(false) {}
};
Node SubstitutionMap::internalSubstitute(TNode t, NodeMap& substitutionCache) {
Debug("substitution::internal") << "SubstitutionMap::internalSubstitute(" << t << ")" << std::endl;
// If nothing to substitute just return the node
if (substitutionCache.empty()) {
return t;
}
// Do a topological sort of the subexpressions and substitute them
vector<substitution_stack_element> toVisit;
toVisit.push_back((TNode) t);
while (!toVisit.empty())
{
// The current node we are processing
substitution_stack_element& stackHead = toVisit.back();
TNode current = stackHead.node;
Debug("substitution::internal") << "SubstitutionMap::internalSubstitute(" << t << "): processing " << current << std::endl;
// If node already in the cache we're done, pop from the stack
NodeMap::iterator find = substitutionCache.find(current);
if (find != substitutionCache.end()) {
toVisit.pop_back();
continue;
}
// Not yet substituted, so process
if (stackHead.children_added) {
// Children have been processed, so substitute
NodeBuilder<> builder(current.getKind());
if (current.getMetaKind() == kind::metakind::PARAMETERIZED) {
builder << current.getOperator();
}
for (unsigned i = 0; i < current.getNumChildren(); ++ i) {
Assert(substitutionCache.find(current[i]) != substitutionCache.end());
builder << substitutionCache[current[i]];
}
// Mark the substitution and continue
Node result = builder;
Debug("substitution::internal") << "SubstitutionMap::internalSubstitute(" << t << "): setting " << current << " -> " << result << std::endl;
substitutionCache[current] = result;
toVisit.pop_back();
} else {
// Mark that we have added the children if any
if (current.getNumChildren() > 0) {
stackHead.children_added = true;
// We need to add the children
for(TNode::iterator child_it = current.begin(); child_it != current.end(); ++ child_it) {
TNode childNode = *child_it;
NodeMap::iterator childFind = substitutionCache.find(childNode);
if (childFind == substitutionCache.end()) {
toVisit.push_back(childNode);
}
}
} else {
// No children, so we're done
Debug("substitution::internal") << "SubstitutionMap::internalSubstitute(" << t << "): setting " << current << " -> " << current << std::endl;
substitutionCache[current] = current;
toVisit.pop_back();
}
}
}
// Return the substituted version
return substitutionCache[t];
}
void SubstitutionMap::addSubstitution(TNode x, TNode t, bool invalidateCache) {
Debug("substitution") << "SubstitutionMap::addSubstitution(" << x << ", " << t << ")" << std::endl;
Assert(d_substitutions.find(x) == d_substitutions.end());
// Temporary substitution cache
NodeMap tempCache;
tempCache[x] = t;
// Put in the new substitutions into the old ones
NodeMap::iterator it = d_substitutions.begin();
NodeMap::iterator it_end = d_substitutions.end();
for(; it != it_end; ++ it) {
it->second = internalSubstitute(it->second, tempCache);
}
// Put the new substitution in
d_substitutions[x] = t;
// Also invalidate the cache
if (invalidateCache) {
d_cacheInvalidated = true;
}
}
bool check(TNode node, const SubstitutionMap::NodeMap& substitutions) {
SubstitutionMap::NodeMap::const_iterator it = substitutions.begin();
SubstitutionMap::NodeMap::const_iterator it_end = substitutions.end();
for (; it != it_end; ++ it) {
if (node.hasSubterm(it->first)) {
return false;
}
}
return true;
}
Node SubstitutionMap::apply(TNode t) {
Debug("substitution") << "SubstitutionMap::apply(" << t << ")" << std::endl;
// Setup the cache
if (d_cacheInvalidated) {
d_substitutionCache = d_substitutions;
d_cacheInvalidated = false;
}
// Perform the substitution
Node result = internalSubstitute(t, d_substitutionCache);
Debug("substitution") << "SubstitutionMap::apply(" << t << ") => " << result << std::endl;
Assert(check(result, d_substitutions));
return result;
}
void SubstitutionMap::print(ostream& out) const {
NodeMap::const_iterator it = d_substitutions.begin();
NodeMap::const_iterator it_end = d_substitutions.end();
for (; it != it_end; ++ it) {
out << it->first << " -> " << it->second << endl;
}
}
}/* CVC4::theory namespace */
}/* CVC4 namespace */
|
