Exercise 3
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| IBM ILOG Solver User's Manual > More on Solving > Setting Filter Levels: Coloring Graphs > Suggested answers > Exercise 3 |
Exercise 3 |
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Remove the redundant IloDistribute constraint from the graph coloring program by commenting out the code you added in Step 10. Run the tests on cliques of size 27, 29, and 31 and compare your results to those you obtained using the redundant constraint. How are they affected?
The results will vary depending on platform, machine, configuration, and so on.
Results using the IloDistribute constraint:
-------------------------------------- IloExtendedLevel clique size:27 #fails: 0 cpu time: 0.651 s IloMediumLevel clique size:27 #fails: 1 cpu time: 0.09 s IloBasicLevel clique size:27 #fails: 1 cpu time: 0.05 s -------------------------------------- IloExtendedLevel clique size:29 #fails: 4 cpu time: 0.541 s IloMediumLevel clique size:29 #fails: 7 cpu time: 0.11 s IloBasicLevel clique size:29 #fails: 23 cpu time: 0.07 s -------------------------------------- IloExtendedLevel clique size:31 #fails: 4 cpu time: 0.751 s IloMediumLevel clique size:31 #fails: 49 cpu time: 0.16 s IloBasicLevel clique size:31 #fails: 65 cpu time: 0.11 s
When you do not use the IloDistribute constraint, there is no effect on the number of fails and little effect on the solution time for the IloExtendedLevel filter level for clique size 27. However, you will not have any response using filter levels IloMediumLevel and IloBasicLevel for many hours. As you can see, the IloDistribute constraint has a large impact on performance for these filter levels.
Results without the IloDistribute constraint:
-------------------------------------- IloExtendedLevel clique size:27 #fails: 0 cpu time: 0.54 s
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