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Questions tagged [optimality-gap]

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How to achieve recording the change of objective or primal gap in solving MILP by SCIP?

I am a solver beginner, would like to ask you how to call the solver to achieve second-level recording, as documented in many articles, as shown below.
Paul's user avatar
  • 11
0 votes
0 answers
107 views

Calculating optimality gap when denominator goes to zero

Using an optimality gap formula that calculates an average over large sets of instances is a common practice to assess the efficiency of an algorithm. The widely-used formula employed by CPLEX is: |...
majid yazdani's user avatar
6 votes
1 answer
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What exactly is the optimality-gap or what does it say in integer linear programming?

I am working since a few months with gurobi and did figure out, that the gap says how far a feasible solutions is away from the optimal solution. However, what does say it exactly? The gurobi docs ...
Mike's user avatar
  • 147
3 votes
1 answer
248 views

LocalSolver at 100% Gap

Can somebody help me with Localsolver? I have installed the academic license and want to solve Split Delivery VRP. I'm using the same model as seen in the website here and using the same instances too ...
overboxed's user avatar
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2 votes
2 answers
2k views

Pyomo mipgap status monitoring

Is there a way to monitor the value of the mipgap while running an optimization model Pyomo? I would like to know how far I am from the optimality gap. Here is my ...
Alireza Asadi's user avatar
2 votes
3 answers
445 views

Does a pre-calculated lower bound of an MILP problem help?

I have an MILP model, say $$ \begin{array}{rl} \mbox{minimize} &f_1(x) + f_2(x)\\ \mbox{subject to} &x\in X \end{array} $$ which is hard to solve. And I find it simple to solve the two ...
xd y's user avatar
  • 1,196
2 votes
1 answer
302 views

What is an acceptable gap for a lower-bound?

Based on your experience, I want to know what is called an acceptable lower-bound. I know it can be different based on the problem. For example, is 5% is an acceptable lower-bound gap for VRPTW? By ...
Mehdi's user avatar
  • 683