• Set variables in the branch and bound tree

    From carlosrd306@gmail.com@21:1/5 to All on Thu Feb 9 12:26:20 2017
    i have an MIP problem in gams with binary variables, i need to fix the branch and bound variables to be efectely zero or one. is there a way to do?

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  • From Paul@21:1/5 to All on Thu Feb 9 14:57:45 2017
    If you mean you want to fix them before solving the model, just set lower bound = upper bound = 0 or lower bound = upper bound = 1, depending on what value you want.

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  • From dgsm0607@gmail.com@21:1/5 to All on Fri Feb 10 18:13:39 2017
    Tank you Paul, we actually are loking for the branch and bound tree to exclusively look for values equal to zero or one since we have a binary variables it does not make sense to look for values different than zero or one in the branches. is there a way
    to do?

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  • From Paul@21:1/5 to All on Sat Feb 11 13:15:44 2017
    If you specify the variables as binary (or specify them as integer and set lower bound 0, upper bound 1 on each), that happens automatically. Solutions to the node LPs may contain fractional values, but whenever a node is separated on variable x, one of
    the children will have x = 0 and the other will have x = 1.

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