c34026b101
note: done using ```sh git grep -l "2010-2024 Google" | xargs sed -i 's/2010-2024 Google/2010-2025 Google/' ```
282 lines
13 KiB
C#
282 lines
13 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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using Google.OrTools.ConstraintSolver;
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using Google.OrTools.Graph;
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.Linq;
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using System;
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public class SpeakerScheduling
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{
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public class FlowAssign : NetDecisionBuilder
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{
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public FlowAssign(IntVar[] vars, int first_slot, IntVar last_slot_var)
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{
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vars_ = vars;
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first_slot_ = first_slot;
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last_slot_var_ = last_slot_var;
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}
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public override Decision Next(Solver solver)
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{
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int large = 100000;
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int number_of_variables = vars_.Length;
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long last_slot = last_slot_var_.Max();
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// Lets build a bipartite graph with equal number of nodes left and right.
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// Variables will be on the left, slots on the right.
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// We will add dummy variables when needed.
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// Arcs will have a cost x is slot x is possible for a variable, a large
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// number otherwise. For dummy variables, the cost will be 0 always.
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LinearSumAssignment matching = new LinearSumAssignment();
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for (int speaker = 0; speaker < number_of_variables; ++speaker)
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{
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IntVar var = vars_[speaker];
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for (int value = first_slot_; value <= last_slot; ++value)
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{
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if (var.Contains(value))
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{
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matching.AddArcWithCost(speaker, value - first_slot_, value);
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}
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else
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{
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matching.AddArcWithCost(speaker, value - first_slot_, large);
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}
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}
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}
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// The Matching algorithms expect the same number of left and right nodes.
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// So we fill the rest with dense zero-cost arcs.
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for (int dummy = number_of_variables; dummy <= last_slot - first_slot_; ++dummy)
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{
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for (int value = first_slot_; value <= last_slot; ++value)
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{
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matching.AddArcWithCost(dummy, value - first_slot_, 0);
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}
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}
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if (matching.Solve() == LinearSumAssignment.Status.OPTIMAL &&
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matching.OptimalCost() < large) // No violated arcs.
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{
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for (int speaker = 0; speaker < number_of_variables; ++speaker)
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{
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vars_[speaker].SetValue(matching.RightMate(speaker) + first_slot_);
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}
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}
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else
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{
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solver.Fail();
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}
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return null;
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}
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private IntVar[] vars_;
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private int first_slot_;
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private IntVar last_slot_var_;
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}
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private static void Solve(int first_slot)
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{
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Console.WriteLine("----------------------------------------------------");
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Solver solver = new Solver("SpeakerScheduling");
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// the slots each speaker is available
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int[][] speaker_availability = {
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new int[] { 1, 3, 4, 6, 7, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 33, 34, 35,
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36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59 },
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new int[] { 1, 2, 7, 8, 10, 11, 16, 17, 18, 21, 22, 23, 24, 25, 33, 34, 35, 36, 37, 38,
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39, 40, 42, 43, 44, 45, 46, 47, 48, 49, 52, 53, 54, 55, 56, 57, 58, 59, 60 },
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new int[] { 5, 6, 7, 10, 12, 14, 16, 17, 21, 22, 23, 24, 33, 35, 37, 38,
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39, 40, 41, 42, 43, 44, 45, 46, 51, 53, 55, 56, 57, 58, 59 },
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new int[] { 1, 2, 3, 4, 5, 6, 7, 11, 13, 14, 15, 16, 20, 24, 25, 33, 34, 35, 37, 38,
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39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60 },
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new int[] { 4, 7, 8, 9, 16, 17, 19, 20, 21, 22, 23, 24, 25, 33, 34, 35, 36,
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37, 38, 39, 40, 41, 42, 43, 49, 50, 51, 53, 55, 56, 57, 58, 59, 60 },
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new int[] { 4, 7, 9, 11, 12, 13, 14, 15, 16, 17, 18, 22, 23, 24, 33, 34,
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35, 36, 38, 39, 42, 44, 46, 48, 49, 51, 53, 54, 55, 56, 57 },
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new int[] { 1, 2, 3, 4, 5, 6, 7, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 54, 55, 56, 57, 58, 59, 60 },
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new int[] { 1, 3, 11, 14, 15, 16, 17, 21, 22, 23, 24, 25, 33, 35, 36, 37, 39, 40,
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41, 42, 43, 44, 45, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 },
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new int[] { 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 18, 19, 20, 21, 22, 23, 24, 25, 33, 34, 35,
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36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 50, 51, 52, 53, 54, 55, 56, 57, 59, 60 },
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new int[] { 24, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 45,
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49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 },
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new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18,
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19, 20, 22, 23, 24, 25, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,
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44, 45, 46, 47, 48, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60 },
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new int[] { 3, 4, 5, 6, 13, 15, 16, 17, 18, 19, 21, 22, 24, 25, 33, 34, 35,
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36, 37, 39, 40, 41, 42, 43, 44, 45, 47, 52, 53, 55, 57, 58, 59, 60 },
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new int[] { 4, 5, 6, 8, 11, 12, 13, 14, 17, 19, 20, 22, 23, 24, 25, 33, 34,
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35, 36, 37, 39, 40, 41, 42, 43, 47, 48, 49, 50, 51, 52, 55, 56, 57 },
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new int[] { 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
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20, 21, 22, 23, 24, 25, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,
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45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 },
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new int[] { 12, 25, 33, 35, 36, 37, 39, 41, 42, 43, 48, 51, 52, 53, 54, 57, 59, 60 },
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new int[] { 4, 8, 16, 17, 19, 23, 25, 33, 34, 35, 37, 41, 44, 45, 47, 48, 49, 50 },
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new int[] { 3, 23, 24, 25, 33, 35, 36, 37, 38, 39, 40, 42, 43, 44, 49, 50, 53, 54, 55, 56, 57, 58, 60 },
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new int[] { 7, 13, 19, 20, 22, 23, 24, 25, 33, 34, 35, 38, 40, 41,
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42, 44, 45, 46, 47, 48, 49, 52, 53, 54, 58, 59, 60 }
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};
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// how long each talk lasts for each speaker
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int[] durations = { 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
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int sum_of_durations = durations.Sum();
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int number_of_speakers = durations.Length;
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// calculate the total number of slots (maximum in the availability array)
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// (and add the max durations)
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int last_slot = (from s in Enumerable.Range(0, number_of_speakers) select speaker_availability[s].Max()).Max();
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Console.WriteLine("Scheduling {0} speakers, for a total of {1} slots, during [{2}..{3}]", number_of_speakers,
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sum_of_durations, first_slot, last_slot);
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// Start variable for all talks.
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IntVar[] starts = new IntVar[number_of_speakers];
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// We store the possible starts for all talks filtered from the
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// duration and the speaker availability.
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int[][] possible_starts = new int [number_of_speakers][];
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for (int speaker = 0; speaker < number_of_speakers; ++speaker)
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{
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int duration = durations[speaker];
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// Let's filter the possible starts.
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List<int> filtered_starts = new List<int>();
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int availability = speaker_availability[speaker].Length;
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for (int index = 0; index < availability; ++index)
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{
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bool ok = true;
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int slot = speaker_availability[speaker][index];
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if (slot < first_slot)
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{
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continue;
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}
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for (int offset = 1; offset < duration; ++offset)
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{
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if (index + offset >= availability ||
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speaker_availability[speaker][index + offset] != slot + offset)
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{
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// discontinuity.
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ok = false;
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break;
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}
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}
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if (ok)
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{
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filtered_starts.Add(slot);
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}
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possible_starts[speaker] = filtered_starts.ToArray();
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}
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starts[speaker] = solver.MakeIntVar(possible_starts[speaker], "start[" + speaker + "]");
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}
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List<IntVar>[] contributions_per_slot = new List<IntVar>[last_slot + 1];
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for (int slot = first_slot; slot <= last_slot; ++slot)
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{
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contributions_per_slot[slot] = new List<IntVar>();
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}
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for (int speaker = 0; speaker < number_of_speakers; ++speaker)
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{
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int duration = durations[speaker];
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IntVar start_var = starts[speaker];
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foreach (int start in possible_starts[speaker])
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{
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for (int offset = 0; offset < duration; ++offset)
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{
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contributions_per_slot[start + offset].Add(start_var.IsEqual(start));
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}
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}
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}
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// Force the schedule to be consistent.
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for (int slot = first_slot; slot <= last_slot; ++slot)
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{
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solver.Add(solver.MakeSumLessOrEqual(contributions_per_slot[slot].ToArray(), 1));
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}
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// Add minimum start info.
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for (int speaker = 0; speaker < number_of_speakers; ++speaker)
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{
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solver.Add(starts[speaker] >= first_slot);
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}
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// Creates makespan.
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IntVar[] end_times = new IntVar[number_of_speakers];
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for (int speaker = 0; speaker < number_of_speakers; speaker++)
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{
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end_times[speaker] = (starts[speaker] + (durations[speaker] - 1)).Var();
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}
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IntVar last_slot_var = end_times.Max().VarWithName("last_slot");
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// Add trivial bound to objective.
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last_slot_var.SetMin(first_slot + sum_of_durations - 1);
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// Redundant scheduling constraint.
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IntervalVar[] intervals = solver.MakeFixedDurationIntervalVarArray(starts, durations, "intervals");
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DisjunctiveConstraint disjunctive = solver.MakeDisjunctiveConstraint(intervals, "disjunctive");
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solver.Add(disjunctive);
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//
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// Search
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//
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List<IntVar> short_talks = new List<IntVar>();
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List<IntVar> long_talks = new List<IntVar>();
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for (int speaker = 0; speaker < number_of_speakers; ++speaker)
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{
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if (durations[speaker] == 1)
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{
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short_talks.Add(starts[speaker]);
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}
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else
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{
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long_talks.Add(starts[speaker]);
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}
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}
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OptimizeVar objective_monitor = solver.MakeMinimize(last_slot_var, 1);
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DecisionBuilder long_phase =
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solver.MakePhase(long_talks.ToArray(), Solver.CHOOSE_MIN_SIZE_LOWEST_MIN, Solver.ASSIGN_MIN_VALUE);
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DecisionBuilder short_phase = new FlowAssign(short_talks.ToArray(), first_slot, last_slot_var);
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DecisionBuilder obj_phase =
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solver.MakePhase(last_slot_var, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MIN_VALUE);
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DecisionBuilder main_phase = solver.Compose(long_phase, short_phase, obj_phase);
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solver.NewSearch(main_phase, objective_monitor);
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while (solver.NextSolution())
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{
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Console.WriteLine("\nLast used slot: " + (last_slot_var.Value()));
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Console.WriteLine("Speakers (start..end):");
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for (int s = 0; s < number_of_speakers; s++)
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{
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long sstart = starts[s].Value();
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Console.WriteLine(" - speaker {0,2}: {1,2}..{2,2}", (s + 1), sstart, (sstart + durations[s] - 1));
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}
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}
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Console.WriteLine("\nSolutions: {0}", solver.Solutions());
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Console.WriteLine("WallTime: {0}ms", solver.WallTime());
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Console.WriteLine("Failures: {0}", solver.Failures());
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Console.WriteLine("Branches: {0} ", solver.Branches());
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solver.EndSearch();
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}
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public static void Main(String[] args)
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{
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int start = 17;
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if (args.Length >= 2)
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{
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start = int.Parse(args[1]);
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}
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Stopwatch s = new Stopwatch();
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s.Start();
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Solve(start);
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s.Stop();
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Console.WriteLine("Finished in " + s.ElapsedMilliseconds + " ms");
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}
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}
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