Decision Optimization

Decision Optimization

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


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  • 1.  warm start with benders

    Posted 10/31/18 10:04 AM

    Originally posted by: brown_rice


    Hello,

     

    When I set strategy 3 for Benders in OPL, is there a way to warm start the model with a heuristic? So say there are two variables in the master problem namely X and Y. I'd like to give partial solution for X and Y and call benders with that. 


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    #OPLusingCPLEXOptimizer


  • 2.  Re: warm start with benders

    Posted 11/02/18 11:15 AM

    Originally posted by: brown_rice


    I'd like to make my question clearer. I want to obtain an initial solution with a heuristic method in order to get a  good lower bound. Then, I want to call benders function. Is that possible? 


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    #OPLusingCPLEXOptimizer


  • 3.  Re: warm start with benders

    Posted 11/05/18 02:20 AM

    Yes, you can use MIP starts to warmstart Benders like any other MIP. See the example opl/examples/opl/warmstart/warmstart.mod shipped with CPLEX for how to do warmstarts in OPL.


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  • 4.  Re: warm start with benders

    Posted 11/23/18 09:58 AM

    Originally posted by: brown_rice


    Hi Daniel,

     

    I have a MILP and I'd like to warm start the entire model and call benders. So it is not like I will only warm start master problem. Do you think that it is still possible? I am currently developing the heuristic but want to make sure beforehand that what I intent to do is applicable.


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    #OPLusingCPLEXOptimizer


  • 5.  Re: warm start with benders

    Posted 11/23/18 10:37 AM

    Actually, what you have in mind is the only thing you can do. You cannot warmstart the master problem (if you chose automatic decomposition then you don't even know what the master problem is). The only thing you can warmstart is the full problem. CPLEX will process your warmstart and do the decomposition only afterwards.


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    #OPLusingCPLEXOptimizer