How to use the function "model.relax()"?
AnsweredUsing relax function of Gurobi can we derive the bound of original model? can it help me simplify the MIP model solving? how can i do this, please give me an example. Thank you!

Hi Ariel,
The first thing Gurobi will do is solving the relaxed model (meaning that all integer/binary constraints are ignored). Afterwards, it will use heuristics and branch and bound to find integer feasible solutions. It might be worth it looking into how a solver optimizes a MIP for you to understand better what is the relaxed model and its use.
I do not see how you could use model.relax to simplify your original model. The bounds of your model should also be easily available when solving the MIP directly.
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Thanks Soares!
I got what the meaning of this, but when i use the "model.relax()" in my program, it seems to ignore almost all constraints as my constraints are seemly all related to binary variables:)
Are there any useful cases that I can learn and refer to?
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Model.relax is useful in very specific cases, it is not common to be used, I can think of one case:
 There are some MIP models which might take too long to get to answer, requiring sophisticated userdefinedheuristics. In order to do this, you might want to optimize the relaxed model first and then use its value to either: set initial solution for the MIP, add constraints/cuts to model, set variable hints.
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Thanks for your careful reply,Soares. I will find the way for optimizing my model based on your advice.
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