how to run gurobi with just gomory algorithm?

Answered

Zehao Zhao

• December 14, 2022 20:09

I want to turnoff all other methods, including branch and bound. I just want to run gomory algorithm. I want to test if my version of algorithm works better than gomory's algorithm on specifc problems. I know you can do:

m.setParam(GRB.Param.PreCrush, 0)
m.setParam(GRB.Param.Presolve, 0)
m.setParam(GRB.Param.Cuts, 0)
m.setParam(GRB.Param.Heuristics, 0)

but i am wondering if there are other parameters needed to be set to 0? (for python preferbly)

Related to

• Parameters

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  Jaromił Najman

  Gurobi Staff

  • December 15, 2022 09:12

  I just want to run gomory algorithm

  Do you mean Gomory cuts? Then, in addition to the parameters you already set, you have to set the GomoryPasses parameter as well. A value of 10-50 should be fine. You should not need to set any additional parameters.

  Setting the PreCrush parameter should not be necessary unless you are using a MIPStart (cf. How do I use MIP starts?).

  Best regards, 
  Jaromił

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  Zehao Zhao

  • December 15, 2022 15:29

  

  

  

  thanks for the clearifications. Yes, i mean gomory cuts. Gomorypasses specify the maximum cuts.

  1. I am wondering: if Gurobi has a functionality to only run gomory cuts to solve a pure two-variable integer programming problem?

  2. In addition, say if i want to solve a pure two-variable integer programming problem, what is the fastest way gorobi can do? (what parameters to be setted?)

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  Jaromił Najman

  Gurobi Staff

  • December 15, 2022 16:30

  Yes, i mean gomory cuts. Gomorypasses specify the maximum cuts.

  Cuts=0 turns off all cuts (also Gomory Cuts). Thus, you have to set GomoryPasses.

  if Gurobi has a functionality to only run gomory cuts to solve a pure two-variable integer programming problem?

  You can make Gurobi work with Gomory Cuts only with the settings we discussed in the above comments.

  In addition, say if i want to solve a pure two-variable integer programming problem, what is the fastest way gorobi can do? (what parameters to be setted?)

  Do you mean that your problem consists of only 2 integer variables? I guess that Gurobi would solve this model in presolve. Probably even if presolve is turned off and only some very basics simplification operations are performed. Nevertheless, I would first start with default settings and see how long Gurobi takes. From there, you can have a look at Most important parameters for MIPs.

  Best regards, 
  Jaromił

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