95 lines
3.4 KiB
Python
Executable File
95 lines
3.4 KiB
Python
Executable File
#!/usr/bin/env python3
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# Copyright 2010-2021 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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# [START program]
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# [START import]
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from ortools.graph import pywrapgraph
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# [END import]
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def main():
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"""Solving an Assignment with teams of worker."""
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# [START solver]
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min_cost_flow = pywrapgraph.SimpleMinCostFlow()
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# [END solver]
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# [START data]
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# Define the directed graph for the flow.
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team_A = [1, 3, 5]
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team_B = [2, 4, 6]
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start_nodes = ([0, 0] + [11, 11, 11] + [12, 12, 12] + [
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1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6
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] + [7, 8, 9, 10])
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end_nodes = ([11, 12] + team_A + team_B + [
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7, 8, 9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8,
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9, 10
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] + [13, 13, 13, 13])
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capacities = ([2, 2] + [1, 1, 1] + [1, 1, 1] + [
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
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] + [1, 1, 1, 1])
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costs = ([0, 0] + [0, 0, 0] + [0, 0, 0] + [
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90, 76, 75, 70, 35, 85, 55, 65, 125, 95, 90, 105, 45, 110, 95, 115, 60,
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105, 80, 75, 45, 65, 110, 95
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] + [0, 0, 0, 0])
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# Define an array of supplies at each node.
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supplies = [4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -4]
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source = 0
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sink = 13
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# [END data]
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# [START constraints]
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# Add each arc.
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for i in range(0, len(start_nodes)):
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min_cost_flow.AddArcWithCapacityAndUnitCost(start_nodes[i],
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end_nodes[i],
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capacities[i], costs[i])
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# Add node supplies.
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for i in range(0, len(supplies)):
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min_cost_flow.SetNodeSupply(i, supplies[i])
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# [END constraints]
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# [START solve]
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# Find the minimum cost flow between node 0 and node 10.
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status = min_cost_flow.Solve()
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# [END solve]
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# [START print_solution]
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if status == min_cost_flow.OPTIMAL:
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min_cost_flow.Solve()
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print('Total cost = ', min_cost_flow.OptimalCost())
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print()
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for arc in range(min_cost_flow.NumArcs()):
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# Can ignore arcs leading out of source or intermediate nodes, or into sink.
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if (min_cost_flow.Tail(arc) != 0 and min_cost_flow.Tail(arc) != 11
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and min_cost_flow.Tail(arc) != 12
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and min_cost_flow.Head(arc) != 13):
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# Arcs in the solution will have a flow value of 1. There start and end nodes
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# give an assignment of worker to task.
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if min_cost_flow.Flow(arc) > 0:
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print('Worker %d assigned to task %d. Cost = %d' %
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(min_cost_flow.Tail(arc), min_cost_flow.Head(arc),
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min_cost_flow.UnitCost(arc)))
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else:
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print('There was an issue with the min cost flow input.')
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print(f'Status: {status}')
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# [END print_solution]
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if __name__ == '__main__':
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main()
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# [END program]
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