63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
# Copyright 2010-2014 Google
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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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"""Test linear sum assignment on a 4x4 matrix.
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Example taken from:
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http://www.ee.oulu.fi/~mpa/matreng/eem1_2-1.htm with kCost[0][1]
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modified so the optimum solution is unique.
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"""
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from google.apputils import app
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from ortools.graph import pywrapgraph
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def RunAssignmentOn4x4Matrix():
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"""Test linear sum assignment on a 4x4 matrix.
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"""
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num_sources = 4
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num_targets = 4
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cost = [[90, 76, 75, 80],
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[35, 85, 55, 65],
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[125, 95, 90, 105],
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[45, 110, 95, 115]]
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expected_cost = cost[0][3] + cost[1][2] + cost[2][1] + cost[3][0]
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assignment = pywrapgraph.LinearSumAssignment()
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for source in range(0, num_sources):
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for target in range(0, num_targets):
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assignment.AddArcWithCost(source, target, cost[source][target])
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solve_status = assignment.Solve()
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if solve_status == assignment.OPTIMAL:
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print 'Successful solve.'
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print 'Total cost', assignment.OptimalCost(), '/', expected_cost
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for i in range(0, assignment.NumNodes()):
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print 'Left node %d assigned to right node %d with cost %d.' % (
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i,
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assignment.RightMate(i),
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assignment.AssignmentCost(i))
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elif solve_status == assignment.INFEASIBLE:
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print 'No perfect matching exists.'
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elif solve_status == assignment.POSSIBLE_OVERFLOW:
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print 'Some input costs are too large and may cause an integer overflow.'
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def main(unused_argv):
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RunAssignmentOn4x4Matrix()
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if __name__ == '__main__':
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app.run()
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