Decision Optimization

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  • 1.  How to view the benders cuts?

    Posted 2 days ago

    Hi, 

    So I am using the CPLEX internal benders and it is able to solve to optimality. I see in the log output, that it in each iteration as expected benders cuts are added. 

    I wish to see the "cut expressions" that are added in each iteration. Can this be retrieved in some manner? If so How?

    Note that I am using mdl.parameters.strategy = 3. 

    Please do help out. 

    Thanks

    Hariharan Subramanian



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    HARIHARAN SUBRAMANIAN
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  • 2.  RE: How to view the benders cuts?

    Posted yesterday

    Unfortunately there is no access to the cutting-planes added by CPLEX wether they are added in regular search or in a Benders decomposition. 


    There is a way that  is rather low-level that consist in exporting your model as a .sav or .lp and using the CPLEX C interface to load and solve it. You need to add a control callback. In that callback code you can have access to the node linear program with the function CPXgetcallbacknodelp and then you can parse or export the model to see the all constraints and determine those that has been added by the Benders method.  


    You can have a look at https://www.ibm.com/docs/en/icos/22.1.1?topic=g-cpxxgetcallbacknodelp-cpxgetcallbacknodelp

    Philippe


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