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ortools-clone/ortools/sat/drat_proof_handler.cc
Corentin Le Molgat b05315de21 sat: backport from main
2025-09-22 17:24:20 +02:00

129 lines
4.2 KiB
C++

// Copyright 2010-2025 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "ortools/sat/drat_proof_handler.h"
#include <algorithm>
#include <cstdlib>
#include <memory>
#include <vector>
#if !defined(__PORTABLE_PLATFORM__)
#include "ortools/base/file.h"
#endif // !defined(__PORTABLE_PLATFORM__)
#include "absl/log/check.h"
#include "absl/types/span.h"
#include "ortools/base/strong_vector.h"
#include "ortools/sat/drat_checker.h"
#include "ortools/sat/drat_writer.h"
#include "ortools/sat/sat_base.h"
#include "ortools/util/strong_integers.h"
namespace operations_research {
namespace sat {
DratProofHandler::DratProofHandler()
: variable_index_(0), drat_checker_(new DratChecker()) {}
DratProofHandler::DratProofHandler(bool in_binary_format, File* output,
bool check)
: variable_index_(0),
drat_writer_(new DratWriter(in_binary_format, output)) {
if (check) {
drat_checker_ = std::make_unique<DratChecker>();
}
}
void DratProofHandler::ApplyMapping(
const util_intops::StrongVector<BooleanVariable, BooleanVariable>&
mapping) {
util_intops::StrongVector<BooleanVariable, BooleanVariable> new_mapping;
for (BooleanVariable v(0); v < mapping.size(); ++v) {
const BooleanVariable image = mapping[v];
if (image != kNoBooleanVariable) {
if (image >= new_mapping.size())
new_mapping.resize(image.value() + 1, kNoBooleanVariable);
CHECK_EQ(new_mapping[image], kNoBooleanVariable);
new_mapping[image] =
v < reverse_mapping_.size() ? reverse_mapping_[v] : v;
CHECK_NE(new_mapping[image], kNoBooleanVariable);
}
}
std::swap(new_mapping, reverse_mapping_);
}
void DratProofHandler::SetNumVariables(int num_variables) {
CHECK_GE(num_variables, reverse_mapping_.size());
while (reverse_mapping_.size() < num_variables) {
reverse_mapping_.push_back(BooleanVariable(variable_index_++));
}
}
void DratProofHandler::AddOneVariable() {
reverse_mapping_.push_back(BooleanVariable(variable_index_++));
}
void DratProofHandler::AddProblemClause(absl::Span<const Literal> clause) {
if (drat_checker_ != nullptr) {
drat_checker_->AddProblemClause(clause);
}
}
void DratProofHandler::AddClause(absl::Span<const Literal> clause) {
MapClause(clause);
if (drat_checker_ != nullptr) {
drat_checker_->AddInferredClause(values_);
}
if (drat_writer_ != nullptr) {
drat_writer_->AddClause(values_);
}
}
void DratProofHandler::DeleteClause(absl::Span<const Literal> clause) {
MapClause(clause);
if (drat_checker_ != nullptr) {
drat_checker_->DeleteClause(values_);
}
if (drat_writer_ != nullptr) {
drat_writer_->DeleteClause(values_);
}
}
DratChecker::Status DratProofHandler::Check(double max_time_in_seconds) {
if (drat_checker_ != nullptr) {
// The empty clause is not explicitly added by the solver.
drat_checker_->AddInferredClause({});
return drat_checker_->Check(max_time_in_seconds);
}
return DratChecker::Status::UNKNOWN;
}
void DratProofHandler::MapClause(absl::Span<const Literal> clause) {
values_.clear();
for (const Literal l : clause) {
CHECK_LT(l.Variable(), reverse_mapping_.size());
const Literal original_literal =
Literal(reverse_mapping_[l.Variable()], l.IsPositive());
values_.push_back(original_literal);
}
// The sorting is such that new variables appear first. This is important for
// BVA since DRAT-trim only check the RAT property with respect to the first
// variable of the clause.
std::sort(values_.begin(), values_.end(), [](Literal a, Literal b) {
return std::abs(a.SignedValue()) > std::abs(b.SignedValue());
});
}
} // namespace sat
} // namespace operations_research