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Root relaxation solution

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  • Riley Clement
    Gurobi Staff Gurobi Staff

    Hi Hussein,

    The first difference I see in the files is between these two lines:

    Presolve removed 67699 rows and 56301 columns
    Presolve removed 67699 rows and 58086 columns

    There is a class of presolve reductions called "Dual Reductions" which use the objective function to infer ways that the model can be made simplified.  These reductions aim to reduce the feasible region while ensuring at least one optimal solution exists.  Changing the objective function is likely affecting the dual reductions which are applied.  Try setting Presolve=0 and solving, then setting DualReductions=0 and solving, and see how it affects the LP solution.

    - Riley

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