OR-Tools  8.2
drat_proof_handler.cc
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1 // Copyright 2010-2018 Google LLC
2 // Licensed under the Apache License, Version 2.0 (the "License");
3 // you may not use this file except in compliance with the License.
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5 //
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8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13 
15 
16 #include <algorithm>
17 
18 #include "absl/memory/memory.h"
19 #include "ortools/base/int_type.h"
20 #include "ortools/base/logging.h"
22 
23 namespace operations_research {
24 namespace sat {
25 
27  : variable_index_(0), drat_checker_(new DratChecker()) {}
28 
29 DratProofHandler::DratProofHandler(bool in_binary_format, File* output,
30  bool check)
31  : variable_index_(0),
32  drat_writer_(new DratWriter(in_binary_format, output)) {
33  if (check) {
34  drat_checker_ = absl::make_unique<DratChecker>();
35  }
36 }
37 
41  for (BooleanVariable v(0); v < mapping.size(); ++v) {
42  const BooleanVariable image = mapping[v];
43  if (image != kNoBooleanVariable) {
44  if (image >= new_mapping.size())
45  new_mapping.resize(image.value() + 1, kNoBooleanVariable);
46  CHECK_EQ(new_mapping[image], kNoBooleanVariable);
47  new_mapping[image] =
48  v < reverse_mapping_.size() ? reverse_mapping_[v] : v;
49  CHECK_NE(new_mapping[image], kNoBooleanVariable);
50  }
51  }
52  std::swap(new_mapping, reverse_mapping_);
53 }
54 
55 void DratProofHandler::SetNumVariables(int num_variables) {
56  CHECK_GE(num_variables, reverse_mapping_.size());
57  while (reverse_mapping_.size() < num_variables) {
58  reverse_mapping_.push_back(BooleanVariable(variable_index_++));
59  }
60 }
61 
63  reverse_mapping_.push_back(BooleanVariable(variable_index_++));
64 }
65 
66 void DratProofHandler::AddProblemClause(absl::Span<const Literal> clause) {
67  if (drat_checker_ != nullptr) {
68  drat_checker_->AddProblemClause(clause);
69  }
70 }
71 
72 void DratProofHandler::AddClause(absl::Span<const Literal> clause) {
73  MapClause(clause);
74  if (drat_checker_ != nullptr) {
75  drat_checker_->AddInferedClause(values_);
76  }
77  if (drat_writer_ != nullptr) {
78  drat_writer_->AddClause(values_);
79  }
80 }
81 
82 void DratProofHandler::DeleteClause(absl::Span<const Literal> clause) {
83  MapClause(clause);
84  if (drat_checker_ != nullptr) {
85  drat_checker_->DeleteClause(values_);
86  }
87  if (drat_writer_ != nullptr) {
88  drat_writer_->DeleteClause(values_);
89  }
90 }
91 
92 DratChecker::Status DratProofHandler::Check(double max_time_in_seconds) {
93  if (drat_checker_ != nullptr) {
94  // The empty clause is not explicitly added by the solver.
95  drat_checker_->AddInferedClause({});
96  return drat_checker_->Check(max_time_in_seconds);
97  }
98  return DratChecker::Status::UNKNOWN;
99 }
100 
101 void DratProofHandler::MapClause(absl::Span<const Literal> clause) {
102  values_.clear();
103  for (const Literal l : clause) {
104  CHECK_LT(l.Variable(), reverse_mapping_.size());
105  const Literal original_literal =
106  Literal(reverse_mapping_[l.Variable()], l.IsPositive());
107  values_.push_back(original_literal);
108  }
109 
110  // The sorting is such that new variables appear first. This is important for
111  // BVA since DRAT-trim only check the RAT property with respect to the first
112  // variable of the clause.
113  std::sort(values_.begin(), values_.end(), [](Literal a, Literal b) {
114  return std::abs(a.SignedValue()) > std::abs(b.SignedValue());
115  });
116 }
117 
118 } // namespace sat
119 } // namespace operations_research
#define CHECK_LT(val1, val2)
Definition: base/logging.h:700
#define CHECK_EQ(val1, val2)
Definition: base/logging.h:697
#define CHECK_GE(val1, val2)
Definition: base/logging.h:701
#define CHECK_NE(val1, val2)
Definition: base/logging.h:698
Definition: base/file.h:32
void resize(size_type new_size)
size_type size() const
void push_back(const value_type &x)
void DeleteClause(absl::Span< const Literal > clause)
DratChecker::Status Check(double max_time_in_seconds)
void AddProblemClause(absl::Span< const Literal > clause)
void ApplyMapping(const absl::StrongVector< BooleanVariable, BooleanVariable > &mapping)
void AddClause(absl::Span< const Literal > clause)
const BooleanVariable kNoBooleanVariable(-1)
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