Dear Gurobi Team,
I have a very large MILP model with various linearizations, both univariate and bivariate. When I solve the problem - presolve enabled - I get a plausible solution. But when I deactivate presolve, the solution for the system variables as well as the objective function value deviates. It should be mentioned that the solution in this deactivated context is clearly invalid because constraints are not respected.
My guess is that this could be due to my big-M, which is quite large and applies to all constraints and presolve cleans that up and thus no numerical errors show up.
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