Save Julia Gurobi model and load and run with different datainputs

Ongoing

Katinka Klepsch

October 28, 2022 09:37

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I have a Gurobi model in the attached format.

My question is probably fairly simple. I am trying to expand the model and with stochastic data inputs. So I want to run the model with different data inputs (the data inputs being eg. missed_bags). 
My question is - Is it possible to save the model and then load the model in another Julia file where I can run the model with different data inputs. 

```
For iter in iterations
    x_result = Run Gurobi_model(missed_bags).  # get assignment
    for sim in simulations
        data = data + std*rand()
        # compute values based on assignment result
        # some stuff happens here
    end
    # Update missed_bags matrix based on simulation results

end

```

My model is made with the following syntax (this I just and extract)

```

Gurobi_model = Model(Gurobi.Optimizer);

variable(Gurobi_model, x[1:Fa, 1:I], Bin); # Binary variable: 1 if arriving flight fa is assigned to in-feed i
@variable(Gurobi_model, y[1:T], Bin) 

# objective function: Minimise the number of missed bags
@objective(Gurobi_model, Min, sum(x[fa,i]*missed_bags[fa,i] for i=1:I, fa=1:Fa) + sum(500*y[t] for t = 1:T)+ sum(0.5*x[fa,i] for i in [2,3,5,6], fa=1:Fa))

@constraint(Gurobi_model, [fa = 1:Fa], (sum(x[fa,i] for i = 1:I) == 1))

# constraints that ensures to add penalty if loading capacity is violated 

# Solution
optimize!(Gurobi_model)

# print statement
....

```

I hope you guys can help!

0

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 16, 2025 23:26

  This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support.
• 

  Jonasz Staszek

  • Community Moderator

  October 28, 2022 13:32

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  Hi Katinka,

  I'm no expert in Julia, but perhaps it is possible to export a module (in particular I mean to export the methods which you use to generate the model, then load them someplace else and use them with new data)?

  Best regards
  Jonasz

  1
• 

  Katinka Klepsch

  October 30, 2022 17:20

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  Thanks! That helps.

  However I cannot use the variable (eg x) in another fil when I try to use x. And I when I try to return x in my function in the module, it just returns the model instead. Do you know why? :-)

  include("01initial_model_module.jl")

  using JuMP

  using Gurobi

  
  

  using .model_module_test

  path_to_data = "data_final_v1.jl" # path to data

  model = deterministic_model_test(path_to_data)

  optimize!(model)

  if termination_status(model) == MOI.OPTIMAL

        xres=value.(x) ---> ERROR

  end

   

   

   

  0

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