additional argument in callback function

Answered

Zheren Zhang

• April 21, 2023 09:06

Hi 

I'm trying to implement a callback function in which a list of variables that not belong to the model has to be updated when a MIP solution is found. My approach is to add the virable as the argument to the callback function:

def mycallback(model,where,p)

but if I do so, I have to list all arguments of the callback function when I want to optimize my model:

model.optimize(mycallback(model,where,p))

and "where" is apparently not and should not be defined. How can I fix this issue? Thank you!

Best Regards

Zheren

Related to

• Callbacks

0

• 

  Marika Karbstein

  Gurobi Staff

  • April 21, 2023 09:42

  I think you are looking for the following, see the Callback documentation:

  If you would like to pass data to your callback function, you can do so through the Model object. For example, if your program includes the statement model._value = 1 before the optimization begins, then your callback function can query the value of model._value. Note that the name of the user data field must begin with an underscore.

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