348 lines
16 KiB
C++
348 lines
16 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/lrat_checker.h"
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#include "absl/types/span.h"
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#include "gtest/gtest.h"
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#include "ortools/base/gmock.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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namespace {
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TEST(LratCheckerTest, LiteralEquivalentToItsNegationIsUnsat) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({-1, +2})); // +1 => +2
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checker.AddProblemClause(ClauseId(2), Literals({-2, -1})); // +2 => -1
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checker.AddProblemClause(ClauseId(3), Literals({+1, +2})); // -1 => +2
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checker.AddProblemClause(ClauseId(4), Literals({-2, +1})); // +2 => +1
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EXPECT_TRUE(checker.AddInferredClause(ClauseId(5), {Literals({-1})},
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{ClauseId(1), ClauseId(2)}));
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(6), {}, {ClauseId(5), ClauseId(3), ClauseId(4)}));
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EXPECT_TRUE(checker.Check());
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}
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TEST(LratCheckerTest, ValidationStopsAtFirstEmptyClause) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, -2})); // -1 => -2
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checker.AddProblemClause(ClauseId(2), Literals({+2, +3})); // -2 => +3
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checker.AddProblemClause(ClauseId(3), Literals({-3, +2})); // -3 => +2
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checker.AddProblemClause(ClauseId(4), Literals({-2, +1})); // +2 => +1
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checker.AddProblemClause(ClauseId(5), Literals({-1, +4})); // +1 => +4
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// not(a) => ... => a proves that a is true. If the content in the middle is
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// of the same form, not(b) => ... => b, then not(a) => not(b) => ... => b if
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// sufficient to prove a.
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(6), {Literals({+1})}, {ClauseId(1), ClauseId(2), ClauseId(3)}));
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// Using unneeded clauses after that is still valid (here not(a) => not(b) =>
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// c => b => a), even if these clauses would not become unit or empty if they
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// were processed.
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(7), {Literals({+1})},
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{ClauseId(1), ClauseId(2), ClauseId(3), ClauseId(4)}));
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}
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TEST(LratCheckerTest, CheckSuccessWithoutRatClauses) {
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// Example from Fig. 1 of 'Efficient Certified RAT Verification'.
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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checker.AddProblemClause(ClauseId(3), Literals({+2, +3, -4}));
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checker.AddProblemClause(ClauseId(4), Literals({-2, -3, +4}));
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checker.AddProblemClause(ClauseId(5), Literals({-1, -3, -4}));
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checker.AddProblemClause(ClauseId(6), Literals({+1, +3, +4}));
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checker.AddProblemClause(ClauseId(7), Literals({-1, +2, +4}));
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checker.AddProblemClause(ClauseId(8), Literals({+1, -2, -4}));
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EXPECT_TRUE(
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checker.AddInferredClause(ClauseId(9), Literals({+1, +2}),
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{ClauseId(1), ClauseId(6), ClauseId(3)}));
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checker.DeleteClauses({ClauseId(1)});
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EXPECT_TRUE(
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checker.AddInferredClause(ClauseId(10), Literals({+1, +3}),
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{ClauseId(9), ClauseId(8), ClauseId(6)}));
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checker.DeleteClauses({ClauseId(6)});
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(11), Literals({+1}),
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{ClauseId(10), ClauseId(9), ClauseId(4), ClauseId(8)}));
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EXPECT_FALSE(checker.Check());
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checker.DeleteClauses({ClauseId(10), ClauseId(9), ClauseId(8)});
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(12), Literals({+2}),
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{ClauseId(11), ClauseId(7), ClauseId(5), ClauseId(3)}));
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EXPECT_FALSE(checker.Check());
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checker.DeleteClauses({ClauseId(7), ClauseId(3)});
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(13), {},
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{ClauseId(11), ClauseId(12), ClauseId(2), ClauseId(4), ClauseId(5)}));
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EXPECT_TRUE(checker.Check());
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}
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TEST(LratCheckerTest, CheckSuccessWithRatClause) {
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// Example from Fig. 2 of 'Efficient Certified RAT Verification'.
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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checker.AddProblemClause(ClauseId(3), Literals({+2, +3, -4}));
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checker.AddProblemClause(ClauseId(4), Literals({-2, -3, +4}));
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checker.AddProblemClause(ClauseId(5), Literals({-1, -3, -4}));
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checker.AddProblemClause(ClauseId(6), Literals({+1, +3, +4}));
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checker.AddProblemClause(ClauseId(7), Literals({-1, +2, +4}));
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checker.AddProblemClause(ClauseId(8), Literals({+1, -2, -4}));
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(9), Literals({+1}), /*unit_ids=*/{},
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{LratChecker::RatIds{ClauseId(2), {ClauseId(6), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(5), {ClauseId(1), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(7), {ClauseId(6), ClauseId(1)}}}));
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EXPECT_FALSE(checker.Check());
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checker.DeleteClauses({ClauseId(8), ClauseId(6), ClauseId(1)});
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(10), Literals({+2}),
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{ClauseId(9), ClauseId(7), ClauseId(5), ClauseId(3)}));
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EXPECT_FALSE(checker.Check());
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checker.DeleteClauses({ClauseId(7), ClauseId(3)});
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EXPECT_TRUE(checker.AddInferredClause(
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ClauseId(11), {},
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{ClauseId(9), ClauseId(10), ClauseId(2), ClauseId(4), ClauseId(5)}));
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EXPECT_TRUE(checker.Check());
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}
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TEST(LratCheckerTest, CheckSuccessWithRatClausesExtensions) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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checker.AddProblemClause(ClauseId(3), Literals({+2, +3, -4}));
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checker.AddProblemClause(ClauseId(4), Literals({-2, -3, +4}));
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checker.AddProblemClause(ClauseId(5), Literals({-1, -3, -4}));
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checker.AddProblemClause(ClauseId(6), Literals({+1, +3, +4}));
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checker.AddProblemClause(ClauseId(7), Literals({-1, +2, +4}));
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checker.AddProblemClause(ClauseId(8), Literals({+1, -2, -4}));
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EXPECT_TRUE(checker.AddInferredClause(
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// Clause 1 becomes unit ({-3}).
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ClauseId(9), Literals({+1, +2}), {ClauseId(1)},
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// clause 9 ∪ {+3} = {+1, +2, +3} has two complementary literals with
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// clause 2 (+1 and +2). Hence the unit propagation proof is not needed.
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{LratChecker::RatIds{ClauseId(2), {}},
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// Likewise with clause 5 (+1 and +3).
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LratChecker::RatIds{ClauseId(5), {}},
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// If we assume that all the literals of clause 9 ∪ {+3} are false, as
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// well as all those of clause 7 except the negation of the pivot (i.e.,
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// {+2, +4}), then clause 6 is in conflict. But this would not be the
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// case if {+3}, propagated from clause 1 above, was ignored.
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LratChecker::RatIds{ClauseId(7), {ClauseId(6)}}}));
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}
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TEST(LratCheckerTest, ClauseIdAlreadyUsed) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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EXPECT_TRUE(checker.AddProblemClause(ClauseId(1), Literals({+1, +2})));
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EXPECT_FALSE(checker.AddProblemClause(ClauseId(1), Literals({+3, +4})));
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EXPECT_EQ(checker.error_message(), "In clause 1: clause ID 1 already used");
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}
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TEST(LratCheckerTest, ErrorStateIsSticky) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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EXPECT_TRUE(checker.AddProblemClause(ClauseId(1), Literals({+1, +2})));
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EXPECT_FALSE(checker.AddProblemClause(ClauseId(1), Literals({+3, +4})));
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// This clause is valid, but there was an error at a previous step.
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EXPECT_FALSE(checker.AddProblemClause(ClauseId(2), Literals({+5, +6})));
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EXPECT_EQ(checker.error_message(), "In clause 1: clause ID 1 already used");
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}
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TEST(LratCheckerTest, CompleteStateIsSticky) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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EXPECT_TRUE(checker.AddProblemClause(ClauseId(1), Literals({})));
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EXPECT_TRUE(checker.Check());
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// This clause is invalid (ID already used), but it is ignored since the proof
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// is already complete.
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EXPECT_TRUE(checker.AddProblemClause(ClauseId(1), Literals({+1, +2})));
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EXPECT_EQ(checker.error_message(), "");
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}
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TEST(LratCheckerTest, ClauseWithTwoComplementaryLiteralsIsIgnored) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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EXPECT_TRUE(checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -1})));
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// The clause ID is the same as the previous one, but this should be OK as the
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// previous clause should not be ignored.
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EXPECT_TRUE(checker.AddProblemClause(ClauseId(1), Literals({+3, +4})));
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}
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TEST(LratCheckerTest, UnknownUnitClauseId) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2}));
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EXPECT_FALSE(checker.AddInferredClause(ClauseId(2), Literals({+3, +4}),
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{ClauseId(2)}));
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EXPECT_EQ(checker.error_message(), "In clause 2: unit_id 2 not found");
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}
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TEST(LratCheckerTest, UnitClauseIdIsNotUnit) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, +3}));
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EXPECT_FALSE(
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checker.AddInferredClause(ClauseId(2), Literals({+1}), {ClauseId(1)}));
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EXPECT_THAT(checker.error_message(),
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::testing::HasSubstr("In clause 2: unit_id 1 is not unit"));
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}
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TEST(LratCheckerTest, MissingPivotForRatProof) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, +3}));
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EXPECT_FALSE(checker.AddInferredClause(
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ClauseId(2), Literals({}), {}, {LratChecker::RatIds{ClauseId(1), {}}}));
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EXPECT_EQ(checker.error_message(),
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"In clause 2: missing pivot for RAT proof");
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}
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TEST(LratCheckerTest, MissingClauseInRatIds) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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// If the last clause in `unit_ids` is not a conflict, the `rat` proof must be
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// valid (here it is not, since clause 2 contains the negation of the pivot
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// but is not listed).
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EXPECT_FALSE(checker.AddInferredClause(ClauseId(3), Literals({+1, +2}),
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{ClauseId(1)}));
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EXPECT_EQ(checker.error_message(),
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"In clause 3: wrong number of resolvant IDs in RAT proof");
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}
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TEST(LratCheckerTest, DuplicateRatResolvantId) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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checker.AddProblemClause(ClauseId(3), Literals({+2, +3, -4}));
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checker.AddProblemClause(ClauseId(4), Literals({-2, -3, +4}));
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checker.AddProblemClause(ClauseId(5), Literals({-1, -3, -4}));
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checker.AddProblemClause(ClauseId(6), Literals({+1, +3, +4}));
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checker.AddProblemClause(ClauseId(7), Literals({-1, +2, +4}));
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checker.AddProblemClause(ClauseId(8), Literals({+1, -2, -4}));
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EXPECT_FALSE(checker.AddInferredClause(
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ClauseId(9), Literals({+1}), /*unit_ids=*/{},
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{LratChecker::RatIds{ClauseId(2), {ClauseId(6), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(5), {ClauseId(1), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(5), {ClauseId(1), ClauseId(8)}}}));
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EXPECT_EQ(checker.error_message(), "In clause 9: duplicate resolvant_id 5");
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}
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TEST(LratCheckerTest, UnknownRatResolvantId) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2}));
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checker.AddProblemClause(ClauseId(2), Literals({-3, +4}));
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EXPECT_FALSE(
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checker.AddInferredClause(ClauseId(3), Literals({+3, +4}), {},
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{LratChecker::RatIds{ClauseId(3), {}}}));
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EXPECT_EQ(checker.error_message(), "In clause 3: resolvant_id 3 not found");
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}
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TEST(LratCheckerTest, MissingNegatedPivotInRatResolvant) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2}));
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checker.AddProblemClause(ClauseId(2), Literals({-3, +4}));
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EXPECT_FALSE(
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checker.AddInferredClause(ClauseId(3), Literals({+3, +4}), {},
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{LratChecker::RatIds{ClauseId(1), {}}}));
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EXPECT_EQ(checker.error_message(),
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"In clause 3: missing negated pivot in resolvant_id 1");
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}
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TEST(LratCheckerTest, UnknownRatUnitId) {
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2}));
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checker.AddProblemClause(ClauseId(2), Literals({-3, +4}));
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EXPECT_FALSE(checker.AddInferredClause(
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ClauseId(3), Literals({+3, +4}), {},
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{LratChecker::RatIds{ClauseId(2), {ClauseId(3)}}}));
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EXPECT_EQ(checker.error_message(), "In clause 3: rat.unit_id 3 not found");
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}
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TEST(LratCheckerTest, RatUnitClauseIdIsNotUnit) {
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// Example from Fig. 2 of 'Efficient Certified RAT Verification'.
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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checker.AddProblemClause(ClauseId(3), Literals({+2, +3, -4}));
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checker.AddProblemClause(ClauseId(4), Literals({-2, -3, +4}));
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checker.AddProblemClause(ClauseId(5), Literals({-1, -3, -4}));
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checker.AddProblemClause(ClauseId(6), Literals({+1, +3, +4}));
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checker.AddProblemClause(ClauseId(7), Literals({-1, +2, +4}));
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checker.AddProblemClause(ClauseId(8), Literals({+1, -2, -4}));
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EXPECT_FALSE(checker.AddInferredClause(
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ClauseId(9), Literals({+1}), /*unit_ids=*/{},
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{LratChecker::RatIds{ClauseId(2), {ClauseId(7), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(5), {ClauseId(1), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(7), {ClauseId(6), ClauseId(1)}}}));
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EXPECT_EQ(checker.error_message(), "In clause 9: rat.unit_id 7 is not unit");
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}
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TEST(LratCheckerTest, LastRatUnitClauseIdIsNotAConflict) {
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// Example from Fig. 2 of 'Efficient Certified RAT Verification'.
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Model model;
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LratChecker& checker = *model.GetOrCreate<LratChecker>();
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checker.AddProblemClause(ClauseId(1), Literals({+1, +2, -3}));
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checker.AddProblemClause(ClauseId(2), Literals({-1, -2, +3}));
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checker.AddProblemClause(ClauseId(3), Literals({+2, +3, -4}));
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checker.AddProblemClause(ClauseId(4), Literals({-2, -3, +4}));
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checker.AddProblemClause(ClauseId(5), Literals({-1, -3, -4}));
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checker.AddProblemClause(ClauseId(6), Literals({+1, +3, +4}));
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checker.AddProblemClause(ClauseId(7), Literals({-1, +2, +4}));
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checker.AddProblemClause(ClauseId(8), Literals({+1, -2, -4}));
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EXPECT_FALSE(checker.AddInferredClause(
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ClauseId(9), Literals({+1}), /*unit_ids=*/{},
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// Clause 6 does not become empty after propagation (clause 8 missing).
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{LratChecker::RatIds{ClauseId(2), {ClauseId(6)}},
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LratChecker::RatIds{ClauseId(5), {ClauseId(1), ClauseId(8)}},
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LratChecker::RatIds{ClauseId(7), {ClauseId(6), ClauseId(1)}}}));
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EXPECT_EQ(
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checker.error_message(),
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"In clause 9: last unit_id for rat.resolvant_id 2 is not a conflict");
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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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