124 lines
3.5 KiB
Python
Executable File
124 lines
3.5 KiB
Python
Executable File
#!/usr/bin/env python3
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# 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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# [START program]
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"""Assignment with teams of workers."""
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# [START import]
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from ortools.graph.python import min_cost_flow
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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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smcf = min_cost_flow.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 = (
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# fmt: off
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[0, 0]
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+ [11, 11, 11]
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+ [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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# fmt: on
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)
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end_nodes = (
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# fmt: off
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[11, 12]
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+ team_a
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+ 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, 9, 10]
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+ [13, 13, 13, 13]
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# fmt: on
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)
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capacities = (
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# fmt: off
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[2, 2]
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+ [1, 1, 1]
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+ [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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# fmt: on
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)
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costs = (
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# fmt: off
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[0, 0]
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+ [0, 0, 0]
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+ [0, 0, 0]
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+ [90, 76, 75, 70, 35, 85, 55, 65, 125, 95, 90, 105, 45, 110, 95, 115, 60, 105, 80, 75, 45, 65, 110, 95]
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+ [0, 0, 0, 0]
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# fmt: on
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)
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source = 0
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sink = 13
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tasks = 4
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# Define an array of supplies at each node.
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supplies = [tasks, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -tasks]
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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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smcf.add_arc_with_capacity_and_unit_cost(
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start_nodes[i], end_nodes[i], capacities[i], costs[i]
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)
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# Add node supplies.
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for i in range(0, len(supplies)):
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smcf.set_node_supply(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 = smcf.solve()
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# [END solve]
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# [START print_solution]
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if status == smcf.OPTIMAL:
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print("Total cost = ", smcf.optimal_cost())
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print()
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for arc in range(smcf.num_arcs()):
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# Can ignore arcs leading out of source or intermediate, or into sink.
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if (
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smcf.tail(arc) != source
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and smcf.tail(arc) != 11
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and smcf.tail(arc) != 12
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and smcf.head(arc) != sink
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):
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# Arcs in the solution will have a flow value of 1.
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# There start and end nodes give an assignment of worker to task.
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if smcf.flow(arc) > 0:
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print(
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"Worker %d assigned to task %d. Cost = %d"
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% (smcf.tail(arc), smcf.head(arc), smcf.unit_cost(arc))
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)
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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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