104 lines
3.8 KiB
C++
104 lines
3.8 KiB
C++
// Copyright 2010-2025 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef ORTOOLS_SAT_ENFORCEMENT_HELPER_H_
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#define ORTOOLS_SAT_ENFORCEMENT_HELPER_H_
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#include <vector>
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#include "absl/base/attributes.h"
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#include "absl/types/span.h"
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#include "ortools/sat/enforcement.h"
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#include "ortools/sat/integer.h"
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#include "ortools/sat/integer_base.h"
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#include "ortools/sat/model.h"
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#include "ortools/sat/sat_base.h"
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namespace operations_research {
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namespace sat {
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// This is meant as an helper to deal with enforcement for any integer based
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// constraint. It wraps some IntegerTrail functions while making sure the
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// enforcement literals are properly added to the propagation reason.
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class EnforcementHelper {
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public:
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explicit EnforcementHelper(Model* model);
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// Calls `Register` with a callback calling
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// `watcher->CallOnNextPropagate(literal_watcher_id)` if a propagation might
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// be possible.
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EnforcementId Register(absl::Span<const Literal> enforcement_literals,
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GenericLiteralWatcher* watcher,
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int literal_watcher_id);
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// Add the enforcement reason to the given vector.
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void AddEnforcementReason(EnforcementId id,
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std::vector<Literal>* reason) const {
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enforcement_propagator_.AddEnforcementReason(id, reason);
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}
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// Try to propagate when the enforced constraint is not satisfiable.
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// This is currently in O(enforcement_size).
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ABSL_MUST_USE_RESULT bool PropagateWhenFalse(
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EnforcementId id, absl::Span<const Literal> literal_reason,
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absl::Span<const IntegerLiteral> integer_reason);
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ABSL_MUST_USE_RESULT bool Enqueue(
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EnforcementId id, IntegerLiteral i_lit,
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absl::Span<const Literal> literal_reason,
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absl::Span<const IntegerLiteral> integer_reason);
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ABSL_MUST_USE_RESULT bool SafeEnqueue(
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EnforcementId id, IntegerLiteral i_lit,
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absl::Span<const IntegerLiteral> integer_reason);
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ABSL_MUST_USE_RESULT bool ConditionalEnqueue(
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EnforcementId id, Literal lit, IntegerLiteral i_lit,
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absl::Span<const Literal> literal_reason,
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absl::Span<const IntegerLiteral> integer_reason);
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void EnqueueLiteral(EnforcementId id, Literal literal,
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absl::Span<const Literal> literal_reason,
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absl::Span<const IntegerLiteral> integer_reason);
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bool ReportConflict(EnforcementId id,
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absl::Span<const IntegerLiteral> integer_reason) {
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return ReportConflict(id, /*literal_reason=*/{}, integer_reason);
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}
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bool ReportConflict(EnforcementId id,
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absl::Span<const Literal> literal_reason,
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absl::Span<const IntegerLiteral> integer_reason);
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EnforcementStatus Status(EnforcementId id) const {
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return enforcement_propagator_.Status(id);
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}
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// Returns the enforcement literals of the given id.
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absl::Span<const Literal> GetEnforcementLiterals(EnforcementId id) const {
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return enforcement_propagator_.GetEnforcementLiterals(id);
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}
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private:
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EnforcementPropagator& enforcement_propagator_;
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const VariablesAssignment& assignment_;
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IntegerTrail* integer_trail_;
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std::vector<Literal> temp_reason_;
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std::vector<IntegerLiteral> temp_integer_reason_;
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};
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} // namespace sat
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} // namespace operations_research
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#endif // ORTOOLS_SAT_ENFORCEMENT_HELPER_H_
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