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  • Latest Post - ‏2013-02-07T23:11:39Z by SystemAdmin
Uonly
Uonly
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Pinned topic output the MIP with cuts in mps file at the root node?

‏2013-02-07T06:34:02Z |
I have a mip problem and focusing on root node bound using cuts.

I want to output the LP relaxation + cuts that are generated at the root node in mps file.

Is there way that can be done using command line or callback function?

Thanks a lot
Updated on 2013-02-07T23:11:39Z at 2013-02-07T23:11:39Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
    7929 Posts

    Re: output the MIP with cuts in mps file at the root node?

    ‏2013-02-07T22:14:57Z  
    This is a bit of a FAQ. Try searching the forum. I believe the answer is that you can do it with the C API but not with any of the other APIs (nor in the interactive optimizer).

    Paul

    Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
  • SystemAdmin
    SystemAdmin
    7929 Posts

    Re: output the MIP with cuts in mps file at the root node?

    ‏2013-02-07T23:11:39Z  
    This is a bit of a FAQ. Try searching the forum. I believe the answer is that you can do it with the C API but not with any of the other APIs (nor in the interactive optimizer).

    Paul

    Mathematicians are like Frenchmen: whenever you say something to them, they translate it into their own language, and at once it is something entirely different. (Goethe)
    Yes, you need to use a C cut callback. In the callback, get the current nodelp and dump this to disk. The cuts will be the last rows. But note that the nodelp is the LP relaxation, so it does not contain integrality information. To get the MIP with cuts, you need to reintroduce the integrality information manually.