79 lines
3.0 KiB
Java
79 lines
3.0 KiB
Java
// Copyright 2010-2018 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.
|
|
|
|
import com.google.ortools.sat.CpModel;
|
|
import com.google.ortools.sat.CpSolver;
|
|
import com.google.ortools.sat.CpSolverStatus;
|
|
import com.google.ortools.sat.IntVar;
|
|
import com.google.ortools.sat.IntervalVar;
|
|
|
|
/**
|
|
* We want to schedule 3 tasks on 3 weeks excluding weekends, making the final day as early as
|
|
* possible.
|
|
*/
|
|
public class NoOverlapSampleSat {
|
|
static {
|
|
System.loadLibrary("jniortools");
|
|
}
|
|
|
|
public static void main(String[] args) throws Exception {
|
|
CpModel model = new CpModel();
|
|
// Three weeks.
|
|
int horizon = 21;
|
|
|
|
// Task 0, duration 2.
|
|
IntVar start0 = model.newIntVar(0, horizon, "start0");
|
|
int duration0 = 2;
|
|
IntVar end0 = model.newIntVar(0, horizon, "end0");
|
|
IntervalVar task0 = model.newIntervalVar(start0, duration0, end0, "task0");
|
|
|
|
// Task 1, duration 4.
|
|
IntVar start1 = model.newIntVar(0, horizon, "start1");
|
|
int duration1 = 4;
|
|
IntVar end1 = model.newIntVar(0, horizon, "end1");
|
|
IntervalVar task1 = model.newIntervalVar(start1, duration1, end1, "task1");
|
|
|
|
// Task 2, duration 3.
|
|
IntVar start2 = model.newIntVar(0, horizon, "start2");
|
|
int duration2 = 3;
|
|
IntVar end2 = model.newIntVar(0, horizon, "end2");
|
|
IntervalVar task2 = model.newIntervalVar(start2, duration2, end2, "task2");
|
|
|
|
// Weekends.
|
|
IntervalVar weekend0 = model.newFixedInterval(5, 2, "weekend0");
|
|
IntervalVar weekend1 = model.newFixedInterval(12, 2, "weekend1");
|
|
IntervalVar weekend2 = model.newFixedInterval(19, 2, "weekend2");
|
|
|
|
// No Overlap constraint. This constraint enforces that no two intervals can overlap.
|
|
// In this example, as we use 3 fixed intervals that span over weekends, this constraint makes
|
|
// sure that all tasks are executed on weekdays.
|
|
model.addNoOverlap(new IntervalVar[] {task0, task1, task2, weekend0, weekend1, weekend2});
|
|
|
|
// Makespan objective.
|
|
IntVar obj = model.newIntVar(0, horizon, "makespan");
|
|
model.addMaxEquality(obj, new IntVar[] {end0, end1, end2});
|
|
model.minimize(obj);
|
|
|
|
// Creates a solver and solves the model.
|
|
CpSolver solver = new CpSolver();
|
|
CpSolverStatus status = solver.solve(model);
|
|
|
|
if (status == CpSolverStatus.OPTIMAL) {
|
|
System.out.println("Optimal Schedule Length: " + solver.objectiveValue());
|
|
System.out.println("Task 0 starts at " + solver.value(start0));
|
|
System.out.println("Task 1 starts at " + solver.value(start1));
|
|
System.out.println("Task 2 starts at " + solver.value(start2));
|
|
}
|
|
}
|
|
}
|