Decision Optimization

Decision Optimization

Delivers prescriptive analytics capabilities and decision intelligence to improve decision-making.

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  • 1.  CPLEX does not initiate branch and bound process

    Posted Wed October 28, 2020 11:00 AM
    Edited by System Admin Fri January 20, 2023 04:10 PM
    I have an MILP model with binary and continuous variables. When I run the model on small scale data sets, it works fine. The current data set I have has 1000 nodes where it is a network optimization model. When I call cplex.solve(), all I see in the engine log is 

    CPXPARAM_TimeLimit 3600 Found incumbent of value 0.000000 after 0.00 sec. (3.25 ticks) Tried aggregator 1 time. MIP Presolve eliminated 28000 rows and 28000 columns. Reduced MIP has 44003 rows, 44000 columns, and 229000 nonzeros. Reduced MIP has 16000 binaries, 0 generals, 0 SOSs, and 0 indicators. Presolve time = 0.30 sec. (126.34 ticks) Probing time = 1.52 sec. (101.89 ticks) Tried aggregator 1 time. ​


    It has been more than 30 mins, and nothing happens and Java shows that the code is still being run. I've never encountered this issue before. Is it because of the complexity of the model? What are the ways that I can handle this issue?



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  • 2.  RE: CPLEX does not initiate branch and bound process
    Best Answer

    Posted Tue November 03, 2020 01:46 AM
    It is just very time consuming to initiate the b&b tree when the input size is too large.

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    Keji Wei
    Senior Operations Research Developer
    Sabre, Dallas, TX
    Webpage: https://kejiwei.github.io/
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    Original Message


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