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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
|
/********************* */
/*! \file sygus_invariance.cpp
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds, Mathias Preiner
** This file is part of the CVC4 project.
** Copyright (c) 2009-2020 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 Implementation of techniques for sygus invariance tests.
**/
#include "theory/quantifiers/sygus/sygus_invariance.h"
#include "theory/quantifiers/sygus/sygus_pbe.h"
#include "theory/quantifiers/sygus/synth_conjecture.h"
#include "theory/quantifiers/sygus/term_database_sygus.h"
using namespace CVC4::kind;
using namespace std;
namespace CVC4 {
namespace theory {
namespace quantifiers {
void EvalSygusInvarianceTest::init(Node conj, Node var, Node res)
{
d_terms.clear();
// simple miniscope
if ((conj.getKind() == AND || conj.getKind() == OR) && res.isConst())
{
for (const Node& c : conj)
{
d_terms.push_back(c);
}
d_kind = conj.getKind();
d_is_conjunctive = res.getConst<bool>() == (d_kind == AND);
}
else
{
d_terms.push_back(conj);
d_is_conjunctive = true;
}
d_var = var;
d_result = res;
}
Node EvalSygusInvarianceTest::doEvaluateWithUnfolding(TermDbSygus* tds, Node n)
{
return tds->evaluateWithUnfolding(n, d_visited);
}
bool EvalSygusInvarianceTest::invariant(TermDbSygus* tds, Node nvn, Node x)
{
TNode tnvn = nvn;
std::unordered_map<TNode, TNode, TNodeHashFunction> cache;
for (const Node& c : d_terms)
{
Node conj_subs = c.substitute(d_var, tnvn, cache);
Node conj_subs_unfold = doEvaluateWithUnfolding(tds, conj_subs);
Trace("sygus-cref-eval2-debug")
<< " ...check unfolding : " << conj_subs_unfold << std::endl;
Trace("sygus-cref-eval2-debug")
<< " ......from : " << conj_subs << std::endl;
if (conj_subs_unfold != d_result)
{
if (d_is_conjunctive)
{
// ti /--> true implies and( t1, ..., tn ) /--> true, where "/-->" is
// "does not evaluate to".
return false;
}
}
else if (!d_is_conjunctive)
{
// ti --> true implies or( t1, ..., tn ) --> true
return true;
}
Trace("sygus-cref-eval2") << "Evaluation min explain : " << conj_subs
<< " still evaluates to " << d_result
<< " regardless of ";
Trace("sygus-cref-eval2") << x << std::endl;
}
return d_is_conjunctive;
}
void EquivSygusInvarianceTest::init(
TermDbSygus* tds, TypeNode tn, SynthConjecture* aconj, Node e, Node bvr)
{
// compute the current examples
d_bvr = bvr;
Assert(tds != nullptr);
if (aconj != nullptr)
{
ExampleEvalCache* eec = aconj->getExampleEvalCache(e);
if (eec != nullptr)
{
// get the result of evaluating bvr on the examples of enumerator e.
eec->evaluateVec(bvr, d_exo, false);
d_conj = aconj;
d_enum = e;
}
}
}
bool EquivSygusInvarianceTest::invariant(TermDbSygus* tds, Node nvn, Node x)
{
TypeNode tn = nvn.getType();
Node nbv = tds->sygusToBuiltin(nvn, tn);
Node nbvr = tds->getExtRewriter()->extendedRewrite(nbv);
Trace("sygus-sb-mexp-debug") << " min-exp check : " << nbv << " -> " << nbvr
<< std::endl;
bool exc_arg = false;
// equivalent / singular up to normalization
if (nbvr == d_bvr)
{
// gives the same result : then the explanation for the child is irrelevant
exc_arg = true;
Trace("sygus-sb-mexp") << "sb-min-exp : " << tds->sygusToBuiltin(nvn)
<< " is rewritten to " << nbvr;
Trace("sygus-sb-mexp") << " regardless of the content of "
<< tds->sygusToBuiltin(x) << std::endl;
}
else
{
if (nbvr.isVar())
{
TypeNode xtn = x.getType();
if (xtn == tn)
{
Node bx = tds->sygusToBuiltin(x, xtn);
Assert(bx.getType() == nbvr.getType());
if (nbvr == bx)
{
Trace("sygus-sb-mexp") << "sb-min-exp : " << tds->sygusToBuiltin(nvn)
<< " always rewrites to argument " << nbvr
<< std::endl;
// rewrites to the variable : then the explanation of this is
// irrelevant as well
exc_arg = true;
d_bvr = nbvr;
}
}
}
}
// equivalent under examples
if (!exc_arg)
{
if (!d_enum.isNull())
{
bool ex_equiv = true;
ExampleEvalCache* eec = d_conj->getExampleEvalCache(d_enum);
Assert(eec != nullptr);
for (unsigned j = 0, esize = d_exo.size(); j < esize; j++)
{
Node nbvr_ex = eec->evaluate(nbvr, j);
if (nbvr_ex != d_exo[j])
{
ex_equiv = false;
break;
}
}
if (ex_equiv)
{
Trace("sygus-sb-mexp") << "sb-min-exp : " << tds->sygusToBuiltin(nvn);
Trace("sygus-sb-mexp")
<< " is the same w.r.t. examples regardless of the content of "
<< tds->sygusToBuiltin(x) << std::endl;
exc_arg = true;
}
}
}
return exc_arg;
}
bool DivByZeroSygusInvarianceTest::invariant(TermDbSygus* tds, Node nvn, Node x)
{
TypeNode tn = nvn.getType();
Node nbv = tds->sygusToBuiltin(nvn, tn);
Node nbvr = tds->getExtRewriter()->extendedRewrite(nbv);
if (tds->involvesDivByZero(nbvr))
{
Trace("sygus-sb-mexp") << "sb-min-exp : " << tds->sygusToBuiltin(nvn)
<< " involves div-by-zero regardless of "
<< tds->sygusToBuiltin(x) << std::endl;
return true;
}
return false;
}
void NegContainsSygusInvarianceTest::init(Node e,
std::vector<std::vector<Node> >& ex,
std::vector<Node>& exo,
std::vector<unsigned>& ncind)
{
Assert(ex.size() == exo.size());
d_enum = e;
d_ex.insert(d_ex.end(), ex.begin(), ex.end());
d_exo.insert(d_exo.end(), exo.begin(), exo.end());
d_neg_con_indices.insert(d_neg_con_indices.end(), ncind.begin(), ncind.end());
}
bool NegContainsSygusInvarianceTest::invariant(TermDbSygus* tds,
Node nvn,
Node x)
{
if (!d_enum.isNull())
{
TypeNode tn = nvn.getType();
Node nbv = tds->sygusToBuiltin(nvn, tn);
Node nbvr = tds->getExtRewriter()->extendedRewrite(nbv);
// if for any of the examples, it is not contained, then we can exclude
for (unsigned i = 0; i < d_neg_con_indices.size(); i++)
{
unsigned ii = d_neg_con_indices[i];
Assert(ii < d_exo.size());
Node nbvre = tds->evaluateBuiltin(tn, nbvr, d_ex[ii]);
Node out = d_exo[ii];
Node cont =
NodeManager::currentNM()->mkNode(kind::STRING_STRCTN, out, nbvre);
Trace("sygus-pbe-cterm-debug") << "Check: " << cont << std::endl;
Node contr = Rewriter::rewrite(cont);
if (!contr.isConst())
{
if (d_isUniversal)
{
return false;
}
}
else if (contr.getConst<bool>() == d_isUniversal)
{
if (Trace.isOn("sygus-pbe-cterm"))
{
Trace("sygus-pbe-cterm")
<< "PBE-cterm : enumerator : do not consider ";
Trace("sygus-pbe-cterm")
<< nbv << " for any " << tds->sygusToBuiltin(x) << " since "
<< std::endl;
Trace("sygus-pbe-cterm") << " PBE-cterm : for input example : ";
for (unsigned j = 0, size = d_ex[ii].size(); j < size; j++)
{
Trace("sygus-pbe-cterm") << d_ex[ii][j] << " ";
}
Trace("sygus-pbe-cterm") << std::endl;
Trace("sygus-pbe-cterm")
<< " PBE-cterm : this rewrites to : " << nbvre << std::endl;
Trace("sygus-pbe-cterm")
<< " PBE-cterm : and is not in output : " << out << std::endl;
}
return !d_isUniversal;
}
Trace("sygus-pbe-cterm-debug2")
<< "...check failed, rewrites to : " << contr << std::endl;
}
}
return d_isUniversal;
}
} /* CVC4::theory::quantifiers namespace */
} /* CVC4::theory namespace */
} /* CVC4 namespace */
|
