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What happens when I modified the RHS of a constraint (GLPK)?

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问题 I am increasing the RHS of less-than-or-equal constraint of a MIP problem with GLPK. However, sometimes, after re-optimizing, GLPK cannot find any feasible solution within the time limit. So I am guessing it does not check if the previous solution was feasible. Does anybody have any experience with that? Or can point me to a document that is not the source code itself? Also, I would like to know what is the workflow after I add a constraint for any other solver (e.g. Gurobi, Cplex, SCIP, CBC)

Solving an integer linear program: why are solvers claiming a solvable instance is infeasible?

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I'm trying to solve integer programming problems. I've tried both use SCIP and LPSolve For example, given the final values of A and B, I want to solve for valA in the following C# code: Int32 a = 0, b = 0; a = a*-6 + b + 0x74FA - valA; b = b/3 + a + 0x81BE - valA; a = a*-6 + b + 0x74FA - valA; b = b/3 + a + 0x81BE - valA; // a == -86561, b == -32299 Which I implemented as this integer program in lp format (the truncating division causes a few complications): min: ; +valA >= 0; +valA < 92; remAA_sign >= 0; remAA_sign <= 1; remAA <= 2; remAA >= -2; remAA +2 remAA_sign >= 0; remAA +2 remAA_sign <

Solving an integer linear program: why are solvers claiming a solvable instance is infeasible?

阅读更多关于 Solving an integer linear program: why are solvers claiming a solvable instance is infeasible?

问题 I'm trying to solve integer programming problems. I've tried both use SCIP and LPSolve For example, given the final values of A and B, I want to solve for valA in the following C# code: Int32 a = 0, b = 0; a = a*-6 + b + 0x74FA - valA; b = b/3 + a + 0x81BE - valA; a = a*-6 + b + 0x74FA - valA; b = b/3 + a + 0x81BE - valA; // a == -86561, b == -32299 Which I implemented as this integer program in lp format (the truncating division causes a few complications): min: ; +valA >= 0; +valA < 92;