80 lines
3.1 KiB
C++
80 lines
3.1 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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#include "ortools/sat/probing.h"
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#include "absl/types/span.h"
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#include "gtest/gtest.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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#include "ortools/sat/sat_solver.h"
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#include "ortools/util/sorted_interval_list.h"
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namespace operations_research {
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namespace sat {
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namespace {
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TEST(ProbeBooleanVariablesTest, IntegerBoundInference) {
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Model model;
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const BooleanVariable a = model.Add(NewBooleanVariable());
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const IntegerVariable b = model.Add(NewIntegerVariable(0, 10));
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const IntegerVariable c = model.Add(NewIntegerVariable(0, 10));
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// Bound restriction.
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model.Add(Implication({Literal(a, true)},
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IntegerLiteral::GreaterOrEqual(b, IntegerValue(2))));
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model.Add(Implication({Literal(a, false)},
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IntegerLiteral::GreaterOrEqual(b, IntegerValue(3))));
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model.Add(Implication({Literal(a, true)},
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IntegerLiteral::LowerOrEqual(b, IntegerValue(7))));
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model.Add(Implication({Literal(a, false)},
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IntegerLiteral::LowerOrEqual(b, IntegerValue(9))));
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// Hole.
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model.Add(Implication({Literal(a, true)},
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IntegerLiteral::GreaterOrEqual(c, IntegerValue(7))));
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model.Add(Implication({Literal(a, false)},
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IntegerLiteral::LowerOrEqual(c, IntegerValue(4))));
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Prober* prober = model.GetOrCreate<Prober>();
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prober->ProbeBooleanVariables(/*deterministic_time_limit=*/1.0);
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auto* integer_trail = model.GetOrCreate<IntegerTrail>();
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EXPECT_EQ("[2,9]", integer_trail->InitialVariableDomain(b).ToString());
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EXPECT_EQ("[0,4][7,10]", integer_trail->InitialVariableDomain(c).ToString());
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}
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TEST(FailedLiteralProbingRoundTest, TrivialExample) {
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Model model;
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const Literal a(model.Add(NewBooleanVariable()), true);
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const Literal b(model.Add(NewBooleanVariable()), true);
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const Literal c(model.Add(NewBooleanVariable()), true);
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// Setting a to false will result in a constradiction, so a must be true.
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model.Add(ClauseConstraint({a, b, c}));
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model.Add(Implication(a.Negated(), b.Negated()));
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model.Add(Implication(c, a));
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auto* sat_soler = model.GetOrCreate<SatSolver>();
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EXPECT_TRUE(sat_soler->Propagate());
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EXPECT_FALSE(sat_soler->Assignment().LiteralIsAssigned(a));
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EXPECT_TRUE(FailedLiteralProbing(&model).DoOneRound(ProbingOptions()));
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EXPECT_TRUE(sat_soler->Assignment().LiteralIsTrue(a));
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}
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} // namespace
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} // namespace sat
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} // namespace operations_research
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