112 lines
3.6 KiB
C#
112 lines
3.6 KiB
C#
// Copyright 2010-2018 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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using System;
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using System.Collections.Generic;
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using System.Linq;
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using Google.OrTools.Sat;
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public class JobshopFt06Sat {
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public struct Task {
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public Task(IntVar s, IntVar e, IntervalVar i) {
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start = s;
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end = e;
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interval = i;
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}
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public IntVar start;
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public IntVar end;
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public IntervalVar interval;
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}
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static void Main() {
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int[, ] durations = new int[, ]{{1, 3, 6, 7, 3, 6}, {8, 5, 10, 10, 10, 4},
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{5, 4, 8, 9, 1, 7}, {5, 5, 5, 3, 8, 9},
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{9, 3, 5, 4, 3, 1}, {3, 3, 9, 10, 4, 1}};
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int[, ] machines =
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new int[, ]{{2, 0, 1, 3, 5, 4}, {1, 2, 4, 5, 0, 3}, {2, 3, 5, 0, 1, 4},
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{1, 0, 2, 3, 4, 5}, {2, 1, 4, 5, 0, 3}, {1, 3, 5, 0, 4, 2}};
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int num_jobs = durations.GetLength(0);
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int num_machines = durations.GetLength(1);
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var all_jobs = Enumerable.Range(0, num_jobs);
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var all_machines = Enumerable.Range(0, num_machines);
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int horizon = 0;
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foreach (int j in all_jobs) {
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foreach (int m in all_machines) {
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horizon += durations[j, m];
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}
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}
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// Creates the model.
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CpModel model = new CpModel();
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// Creates jobs.
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Task[, ] all_tasks = new Task[num_jobs, num_machines];
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foreach (int j in all_jobs) {
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foreach (int m in all_machines) {
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IntVar start_var =
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model.NewIntVar(0, horizon, String.Format("start_{0}_{1}", j, m));
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int duration = durations[j, m];
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IntVar end_var =
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model.NewIntVar(0, horizon, String.Format("end_{0}_{1}", j, m));
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IntervalVar interval_var =
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model.NewIntervalVar(start_var, duration, end_var,
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String.Format("interval_{0}_{1}", j, m));
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all_tasks[j, m] = new Task(start_var, end_var, interval_var);
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}
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}
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// Create disjuctive constraints.
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List<IntervalVar>[] machine_to_jobs = new List<IntervalVar>[ num_machines ];
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foreach (int m in all_machines) {
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machine_to_jobs[m] = new List<IntervalVar>();
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}
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foreach (int j in all_jobs) {
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foreach (int m in all_machines) {
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machine_to_jobs[machines[j, m]].Add(all_tasks[j, m].interval);
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}
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}
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foreach (int m in all_machines) {
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model.AddNoOverlap(machine_to_jobs[m]);
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}
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// Precedences inside a job.
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foreach (int j in all_jobs) {
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for (int k = 0; k < num_machines - 1; ++k) {
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model.Add(all_tasks[j, k + 1].start >= all_tasks[j, k].end);
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}
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}
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// Makespan objective.
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IntVar[] all_ends = new IntVar[num_jobs];
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foreach (int j in all_jobs) {
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all_ends[j] = all_tasks[j, num_machines - 1].end;
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}
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IntVar makespan = model.NewIntVar(0, horizon, "makespan");
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model.AddMaxEquality(makespan, all_ends);
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model.Minimize(makespan);
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Console.WriteLine(model.ModelStats());
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// Creates the solver and solve.
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CpSolver solver = new CpSolver();
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// Display a few solutions picked at random.
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solver.Solve(model);
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// Statistics.
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Console.WriteLine(solver.ResponseStats());
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}
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}
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