(I apologize. I saw this question but, I do not know these may be the same or not.)
I am trying to solve a MIP problem and have an issue about that. The problem's LP relaxation has the objective value about $63$ but, when the problem is solved by MIP solvers like CPLEX, Gurobi and SCIP, the relax solution is reported $59$. (even though I disable pre-solving, cuts and heuristics).
Root relaxation: objective 5.900000e+01
In all of the cases, the value of the variables are the same and the problem is solved optimality.
I was wondering if, is there any way to get the root relaxation value equal to $63$ by using MIP solvers or this is an advanced technique in which the solvers use to speed up the solving time?