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Training instances

Training instances

Below is a number of training instances that can aid in building a model and a search algorithm for the total waste water network design and operation optimization problem. A few more instances will be added as they become available.


To assess the difficulty of these instances we attempted to solve them with four different solvers using their standard settings; namely: BARON, SCIP, ANTIGON, and BONMIN. A CPU time limit of 3 hours was enforced.

Summary of training instances:

InstanceBest objective value obtained within 3 hoursTerminationRunning time (seconds)SolverDifficulty
Instance1NATimed outTimed outAll fourOpen
Instance2239534.088Gap reached2330SCIPEasy
Instance31231500.817Gap reached4021ANTIGONEEasy
Instance4NATimed outTimed outAll fourOpen
Instance51761352.4108Timed outTimed outAll fourOpen
Instance2-batch3205459.020*Gap reached73BARONOpen
Instance2-batch5799715.934*Gap reached92SCIPOpen
Instance3-batch9534546.068*Gap reached60ANTIGONEOpen
Instance3-batch13847832.49*Gap reached402BARONOpen

*Solution quality of a feasible solution obtained to a problem with a constant objective value. The optimal solution of the cost objective was not reached within the time limit. 

The participants are expected to find better, or optimal, solutions to the ones we found, and/or do so with less time. Proving infeasibility of the open questions also has merit.  

Instance2.txt23.44 KB
Instance1.txt29.72 KB
Instance2-batch.txt23.55 KB
Instance3.txt23.89 KB
Instance3-batch.txt23.96 KB
Instance4.txt27.04 KB
Instance5.txt25.18 KB
Instance2-solution-SCIP.txt15.99 KB
Instance2-solution-ANTIGONE.txt19.6 KB
Instance2-batch-solution-BARON-trivialObj.txt16.99 KB
Instance2-batch-solution-SCIP-trivialObj.txt20.31 KB
Instance3-solution-ANTIGONE.txt43.8 KB
Instance3-batch-solution-BARON-trivialObj.txt99.7 KB
Instance3-batch-solution-ANTIGONE-trivialObj.txt48.01 KB
solutionVerifier.zip10.65 KB