SIGN IN SIGN UP
google / or-tools UNCLAIMED

Google's Operations Research tools:

0 0 1 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.
2021-08-31 11:58:46 +02:00
package com.google.ortools.constraintsolver;
import static com.google.common.truth.Truth.assertThat;
2026-01-28 17:42:53 +01:00
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
2021-09-17 09:44:04 +02:00
import com.google.common.collect.Iterables;
2021-12-10 16:59:43 +01:00
import com.google.ortools.Loader;
2021-08-31 11:58:46 +02:00
import com.google.ortools.constraintsolver.ConstraintSolverParameters;
import com.google.ortools.constraintsolver.RegularLimitParameters;
import java.util.ArrayList;
2019-02-08 13:08:37 +01:00
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Consumer;
import java.util.function.Supplier;
2026-01-28 17:42:53 +01:00
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
/** Tests the Constraint solver java interface. */
2021-08-31 11:58:46 +02:00
public final class ConstraintSolverTest {
2026-01-28 17:42:53 +01:00
@BeforeEach
2021-08-31 11:58:46 +02:00
public void setUp() {
Loader.loadNativeLibraries();
2019-03-29 17:35:04 +01:00
}
2021-08-31 11:58:46 +02:00
@Test
public void testSolverCtor() {
final Solver solver = new Solver("TestSolver");
assertNotNull(solver);
assertEquals("TestSolver", solver.model_name());
assertNotNull(solver.toString());
}
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testIntVar() {
final Solver solver = new Solver("Solver");
final IntVar var = solver.makeIntVar(3, 11, "IntVar");
assertEquals(3, var.min());
assertEquals(11, var.max());
assertEquals("IntVar", var.name());
var.setName("renamed");
assertEquals("renamed", var.name());
2021-08-31 11:58:46 +02:00
}
@Test
public void testIntVarArray() {
final Solver solver = new Solver("Solver");
final IntVar[] vars = solver.makeIntVarArray(7, 3, 5, "vars");
assertThat(vars).hasLength(7);
for (IntVar var : vars) {
assertEquals(3, var.min());
assertEquals(5, var.max());
2020-09-23 12:10:52 +02:00
}
}
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testRabbitsPheasants() {
final Solver solver = new Solver("testRabbitsPheasants");
final IntVar rabbits = solver.makeIntVar(0, 100, "rabbits");
final IntVar pheasants = solver.makeIntVar(0, 100, "pheasants");
solver.addConstraint(solver.makeEquality(solver.makeSum(rabbits, pheasants), 20));
solver.addConstraint(solver.makeEquality(
solver.makeSum(solver.makeProd(rabbits, 4), solver.makeProd(pheasants, 2)), 56));
final DecisionBuilder db =
solver.makePhase(rabbits, pheasants, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MIN_VALUE);
solver.newSearch(db);
solver.nextSolution();
assertEquals(8, rabbits.value());
assertEquals(12, pheasants.value());
solver.endSearch();
}
// A Decision builder that does nothing.
static class DummyDecisionBuilder extends JavaDecisionBuilder {
@Override
public Decision next(Solver solver) throws Solver.FailException {
System.out.println("In Dummy Decision Builder");
return null;
2020-09-23 12:10:52 +02:00
}
2021-08-31 11:58:46 +02:00
@Override
public String toString() {
return "DummyDecisionBuilder";
2020-09-23 12:10:52 +02:00
}
}
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testDummyDecisionBuilder() {
final Solver solver = new Solver("testDummyDecisionBuilder");
final DecisionBuilder db = new DummyDecisionBuilder();
assertTrue(solver.solve(db));
}
/**
* A decision builder that fails.
*/
static class FailDecisionBuilder extends JavaDecisionBuilder {
@Override
public Decision next(Solver solver) throws Solver.FailException {
System.out.println("In Fail Decision Builder");
solver.fail();
return null;
2020-09-23 12:10:52 +02:00
}
2021-08-31 11:58:46 +02:00
}
@Test
public void testFailDecisionBuilder() {
final Solver solver = new Solver("testFailDecisionBuilder");
final DecisionBuilder db = new FailDecisionBuilder();
assertFalse(solver.solve(db));
}
/** Golomb Ruler test */
@Test
public void testGolombRuler() {
final int m = 8;
final Solver solver = new Solver("GR " + m);
final IntVar[] ticks = solver.makeIntVarArray(m, 0, (1 << (m + 1)) - 1, "ticks");
solver.addConstraint(solver.makeEquality(ticks[0], 0));
for (int i = 0; i < ticks.length - 1; i++) {
solver.addConstraint(solver.makeLess(ticks[i], ticks[i + 1]));
}
final ArrayList<IntVar> diff = new ArrayList<>();
for (int i = 0; i < m - 1; i++) {
for (int j = i + 1; j < m; j++) {
diff.add(solver.makeDifference(ticks[j], ticks[i]).var());
2020-09-23 12:10:52 +02:00
}
2021-08-31 11:58:46 +02:00
}
solver.addConstraint(solver.makeAllDifferent(diff.toArray(new IntVar[0]), true));
// break symetries
if (m > 2) {
solver.addConstraint(solver.makeLess(diff.get(0), Iterables.getLast(diff)));
}
final OptimizeVar opt = solver.makeMinimize(ticks[m - 1], 1);
final DecisionBuilder db =
solver.makePhase(ticks, Solver.CHOOSE_MIN_SIZE_LOWEST_MIN, Solver.ASSIGN_MIN_VALUE);
final SearchMonitor log = solver.makeSearchLog(10000, opt);
assertTrue(solver.solve(db, opt, log));
assertEquals(34, opt.best());
}
@Test
public void testElementFunction() {
final Solver solver = new Solver("testElementFunction");
final IntVar index = solver.makeIntVar(0, 10, "index");
final IntExpr element = solver.makeElement((long x) -> x * 2, index);
assertEquals(0, element.min());
assertEquals(20, element.max());
}
@Test
public void testSolverParameters() {
2021-12-10 16:59:43 +01:00
final ConstraintSolverParameters parameters =
Solver.defaultSolverParameters().toBuilder().setTraceSearch(true).build();
2021-08-31 11:58:46 +02:00
final Solver solver = new Solver("testSolverParameters", parameters);
final ConstraintSolverParameters stored = solver.parameters();
assertTrue(stored.getTraceSearch());
}
@Test
public void testRegularLimitParameters() {
final Solver solver = new Solver("testRegularLimitParameters");
final RegularLimitParameters protoLimit =
2021-12-10 16:59:43 +01:00
solver.makeDefaultRegularLimitParameters().toBuilder().setFailures(20000).build();
2021-08-31 11:58:46 +02:00
assertEquals(20000, protoLimit.getFailures());
final SearchLimit limit = solver.makeLimit(protoLimit);
assertNotNull(limit);
}
// verify Closure in Decision.
@Test
public void testClosureDecision() {
final StringProperty call = new StringProperty("");
final Solver solver = new Solver("ClosureDecisionTest");
final Decision decision = solver.makeDecision(
(Solver s) -> call.setValue("Apply"), (Solver s) -> call.setValue("Refute"));
System.gc();
decision.apply(solver);
assertEquals("Apply", call.toString());
decision.refute(solver);
assertEquals("Refute", call.toString());
}
@Test
public void testSolverInClosureDecision() {
final Solver solver = new Solver("SolverTestName");
final String modelName = solver.model_name();
// Lambda can only capture final or implicit final.
final AtomicInteger countApply = new AtomicInteger(0);
final AtomicInteger countRefute = new AtomicInteger(0);
assertEquals(0, countApply.intValue());
assertEquals(0, countRefute.intValue());
final Decision decision = solver.makeDecision(
2022-02-16 16:19:26 +01:00
(Solver s)
-> {
2021-08-31 11:58:46 +02:00
assertEquals(s.model_name(), modelName);
countApply.addAndGet(1);
},
(Solver s) -> {
assertEquals(s.model_name(), modelName);
countRefute.addAndGet(1);
});
System.gc(); // verify lambda are kept alive
decision.apply(solver);
assertEquals(1, countApply.intValue());
assertEquals(0, countRefute.intValue());
decision.refute(solver);
assertEquals(1, countApply.intValue());
assertEquals(1, countRefute.intValue());
}
// A Decision builder that does nothing
public static class ActionDecisionBuilder extends JavaDecisionBuilder {
Consumer<Solver> apply;
Consumer<Solver> refute;
boolean passed;
public ActionDecisionBuilder(Consumer<Solver> a, Consumer<Solver> r) {
apply = a;
refute = r;
passed = false;
}
@Override
public Decision next(Solver solver) throws Solver.FailException {
if (passed) {
return null;
2020-09-23 12:10:52 +02:00
}
2021-08-31 11:58:46 +02:00
passed = true;
return solver.makeDecision(apply, refute);
}
2021-08-31 11:58:46 +02:00
@Override
public String toString() {
return "ActionDecisionBuilder";
}
}
// Tests the ActionDecisionBuilder.
@Test
public void testActionDecisionBuilder() {
final Solver solver = new Solver("testActionDecisionBuilder");
// Lambda can only capture final or implicit final
final AtomicInteger countApply = new AtomicInteger(0);
final AtomicInteger countRefute = new AtomicInteger(0);
assertEquals(0, countApply.intValue());
assertEquals(0, countRefute.intValue());
final DecisionBuilder db = new ActionDecisionBuilder(
2022-02-16 16:19:26 +01:00
(Solver s) -> countApply.addAndGet(1), (Solver s) -> countRefute.addAndGet(1));
2021-08-31 11:58:46 +02:00
solver.newSearch(db);
assertTrue(solver.nextSolution());
assertEquals(1, countApply.intValue());
assertEquals(0, countRefute.intValue());
assertTrue(solver.nextSolution());
assertEquals(1, countApply.intValue());
assertEquals(1, countRefute.intValue());
solver.endSearch();
}
2021-08-31 11:58:46 +02:00
// ----- LocalSearch Test -----
2020-09-14 23:49:23 +02:00
private static class MoveOneVar extends IntVarLocalSearchOperator {
public MoveOneVar(IntVar[] variables) {
super(variables);
variableIndex = 0;
moveUp = false;
}
@Override
protected boolean oneNeighbor() {
long currentValue = oldValue(variableIndex);
if (moveUp) {
setValue(variableIndex, currentValue + 1);
variableIndex = (variableIndex + 1) % size();
} else {
setValue(variableIndex, currentValue - 1);
}
moveUp = !moveUp;
return true;
}
@Override
public void onStart() {}
// Index of the next variable to try to restore
private long variableIndex;
// Direction of the modification.
private boolean moveUp;
}
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testSolver() {
final Solver solver = new Solver("Solver");
final IntVar[] vars = solver.makeIntVarArray(4, 0, 4, "vars");
final IntVar sumVar = solver.makeSum(vars).var();
final OptimizeVar obj = solver.makeMinimize(sumVar, 1);
final DecisionBuilder db =
solver.makePhase(vars, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MAX_VALUE);
2021-08-31 11:58:46 +02:00
final MoveOneVar moveOneVar = new MoveOneVar(vars);
final LocalSearchPhaseParameters lsParams =
2020-09-23 12:10:52 +02:00
solver.makeLocalSearchPhaseParameters(sumVar, moveOneVar, db);
2021-08-31 11:58:46 +02:00
final DecisionBuilder ls = solver.makeLocalSearchPhase(vars, db, lsParams);
final SolutionCollector collector = solver.makeLastSolutionCollector();
collector.addObjective(sumVar);
2021-08-31 11:58:46 +02:00
final SearchMonitor log = solver.makeSearchLog(1000, obj);
assertTrue(solver.solve(ls, collector, obj, log));
}
2020-09-14 23:49:23 +02:00
private static class SumFilter extends IntVarLocalSearchFilter {
public SumFilter(IntVar[] vars) {
super(vars);
sum = 0;
}
@Override
protected void onSynchronize(Assignment unusedDelta) {
sum = 0;
for (int index = 0; index < size(); ++index) {
sum += value(index);
}
}
@Override
2019-08-06 15:57:08 -07:00
public boolean accept(Assignment delta, Assignment unusedDeltadelta, long unusedObjectiveMin,
2020-09-23 12:10:52 +02:00
long unusedObjectiveMax) {
AssignmentIntContainer solutionDelta = delta.intVarContainer();
int solutionDeltaSize = solutionDelta.size();
for (int i = 0; i < solutionDeltaSize; ++i) {
if (!solutionDelta.element(i).activated()) {
return true;
}
}
long newSum = sum;
for (int index = 0; index < solutionDeltaSize; ++index) {
int touchedVar = index(solutionDelta.element(index).var());
long oldValue = value(touchedVar);
long newValue = solutionDelta.element(index).value();
newSum += newValue - oldValue;
}
return newSum < sum;
}
private long sum;
}
2021-08-31 11:58:46 +02:00
private static class StringProperty {
public StringProperty(String initialValue) {
value = initialValue;
}
public void setValue(String newValue) {
value = newValue;
}
@Override
public String toString() {
return value;
}
private String value;
}
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testSolverWithLocalSearchFilter() {
final Solver solver = new Solver("Solver");
final IntVar[] vars = solver.makeIntVarArray(4, 0, 4, "vars");
final IntVar sumVar = solver.makeSum(vars).var();
final OptimizeVar obj = solver.makeMinimize(sumVar, 1);
final DecisionBuilder db =
solver.makePhase(vars, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MAX_VALUE);
MoveOneVar moveOneVar = new MoveOneVar(vars);
SumFilter filter = new SumFilter(vars);
IntVarLocalSearchFilter[] filters = new IntVarLocalSearchFilter[1];
filters[0] = filter;
2021-08-31 11:58:46 +02:00
LocalSearchFilterManager filterManager = new LocalSearchFilterManager(filters);
LocalSearchPhaseParameters lsParams =
2021-08-31 11:58:46 +02:00
solver.makeLocalSearchPhaseParameters(sumVar, moveOneVar, db, null, filterManager);
DecisionBuilder ls = solver.makeLocalSearchPhase(vars, db, lsParams);
SolutionCollector collector = solver.makeLastSolutionCollector();
collector.addObjective(sumVar);
SearchMonitor log = solver.makeSearchLog(1000, obj);
solver.solve(ls, collector, obj, log);
}
2020-09-14 23:49:23 +02:00
private static class OneVarLns extends BaseLns {
public OneVarLns(IntVar[] vars) {
super(vars);
}
@Override
public void initFragments() {
2021-08-31 11:58:46 +02:00
index = 0;
}
@Override
public boolean nextFragment() {
int size = size();
2021-08-31 11:58:46 +02:00
if (index < size) {
appendToFragment(index);
++index;
return true;
} else {
return false;
}
}
2021-08-31 11:58:46 +02:00
private int index;
}
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testSolverLns() {
final Solver solver = new Solver("Solver");
final IntVar[] vars = solver.makeIntVarArray(4, 0, 4, "vars");
final IntVar sumVar = solver.makeSum(vars).var();
final OptimizeVar obj = solver.makeMinimize(sumVar, 1);
final DecisionBuilder db =
solver.makePhase(vars, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MAX_VALUE);
2021-08-31 11:58:46 +02:00
final OneVarLns oneVarLns = new OneVarLns(vars);
final LocalSearchPhaseParameters lsParams =
2020-09-23 12:10:52 +02:00
solver.makeLocalSearchPhaseParameters(sumVar, oneVarLns, db);
2021-08-31 11:58:46 +02:00
final DecisionBuilder ls = solver.makeLocalSearchPhase(vars, db, lsParams);
final SolutionCollector collector = solver.makeLastSolutionCollector();
collector.addObjective(sumVar);
2021-08-31 11:58:46 +02:00
final SearchMonitor log = solver.makeSearchLog(1000, obj);
solver.solve(ls, collector, obj, log);
}
2021-08-31 11:58:46 +02:00
// ----- SearchLog Test -----
// TODO(user): Improve search log tests; currently only tests coverage and callback.
// note: this is more or less what is done in search_test.cc
private static void runSearchLog(SearchMonitor searchlog) {
searchlog.enterSearch();
searchlog.exitSearch();
searchlog.acceptSolution();
searchlog.atSolution();
searchlog.beginFail();
searchlog.noMoreSolutions();
searchlog.beginInitialPropagation();
searchlog.endInitialPropagation();
}
// Simple Coverage test...
2020-09-14 23:49:23 +02:00
@Test
2021-08-31 11:58:46 +02:00
public void testSearchLog() {
final Solver solver = new Solver("TestSearchLog");
final IntVar var = solver.makeIntVar(1, 1, "Variable");
solver.makeMinimize(var, 1);
final SearchMonitor searchlog = solver.makeSearchLog(0);
runSearchLog(searchlog);
}
2020-09-14 23:49:23 +02:00
private static class SearchCount implements Supplier<String> {
2021-08-31 11:58:46 +02:00
public SearchCount(AtomicInteger initialCount) {
count = initialCount;
}
@Override
2019-02-08 13:08:37 +01:00
public String get() {
count.addAndGet(1);
return "display callback called...";
}
2021-08-31 11:58:46 +02:00
private final AtomicInteger count;
}
2021-08-31 11:58:46 +02:00
@Test
public void testSearchLogWithCallback() {
final Solver solver = new Solver("TestSearchLog");
final AtomicInteger count = new AtomicInteger(0);
2021-09-07 18:39:00 +02:00
final SearchMonitor searchlog = solver.makeSearchLog(0, // branch period
new SearchCount(count));
2021-08-31 11:58:46 +02:00
System.gc(); // verify SearchCount is kept alive by the searchlog
runSearchLog(searchlog);
2021-08-31 11:58:46 +02:00
assertEquals(1, count.intValue());
}
2019-02-08 13:08:37 +01:00
2021-08-31 11:58:46 +02:00
@Test
public void testSearchLogWithLambdaCallback() {
final Solver solver = new Solver("TestSearchLog");
final AtomicInteger count = new AtomicInteger(0);
2021-09-07 18:39:00 +02:00
final SearchMonitor searchlog = solver.makeSearchLog(0, // branch period
2021-08-31 11:58:46 +02:00
() -> {
count.addAndGet(1);
return "display callback called...";
});
System.gc(); // verify lambda is kept alive by the searchlog
runSearchLog(searchlog);
assertEquals(1, count.intValue());
}
2021-08-31 11:58:46 +02:00
@Test
public void testSearchLogWithIntVarCallback() {
final Solver solver = new Solver("TestSearchLog");
final IntVar var = solver.makeIntVar(1, 1, "Variable");
final AtomicInteger count = new AtomicInteger(0);
2021-09-07 18:39:00 +02:00
final SearchMonitor searchlog = solver.makeSearchLog(0, // branch period
2019-02-08 13:08:37 +01:00
var, // IntVar to monitor
new SearchCount(count));
2021-08-31 11:58:46 +02:00
System.gc();
2019-02-08 13:08:37 +01:00
runSearchLog(searchlog);
2021-08-31 11:58:46 +02:00
assertEquals(1, count.intValue());
2019-02-08 13:08:37 +01:00
}
2021-08-31 11:58:46 +02:00
@Test
public void testSearchLogWithObjectiveCallback() {
final Solver solver = new Solver("TestSearchLog");
final IntVar var = solver.makeIntVar(1, 1, "Variable");
final OptimizeVar objective = solver.makeMinimize(var, 1);
final AtomicInteger count = new AtomicInteger(0);
2021-09-07 18:39:00 +02:00
final SearchMonitor searchlog = solver.makeSearchLog(0, // branch period
objective, // objective var to monitor
new SearchCount(count));
2021-08-31 11:58:46 +02:00
System.gc();
runSearchLog(searchlog);
2021-08-31 11:58:46 +02:00
assertEquals(1, count.intValue());
}
}