Gurobi as a function

Answered

Akbar Rugova

October 29, 2023 13:26

Dear Gurobi Professional,

I currently have a problem regarding incorporation of gurobi as a function.

The intended purpose is that I can eventually extract the solution and plot it using plotly in a single script

The code:

def UPMSet(jobs,machines,workers,activities,oprttime,machining,moving,B):
    from gurobipy import GRB
    m = Model()
    x = {}
    for k in workers:
        for h in machines:
            for a in activities:
                for j in range (0, len(jobs)+1):
                    for i in machines:
                        for b in activities:
                            for l in jobs:
                                x[k,h,a,j,i,b,l] = m.addVar(vtype=GRB.BINARY,name='x_%s_%s_%s_%s_%s_%s_%s' % (k,h,a,j,i,b,l))

 

However, there's an error saying:

name 'Model' is not defined

Apparently the m = Model() is not defined. I recon there's a problem in the first 2 line of the code but Im not really sure.

I can normally run the gurobi code on its own but when it comes to include it as a function it fails me.

I'm quite new to gurobi and some of my explanation might be a wrong and a bit confusing but thats the broad idea.

Could you help me sort this problem out?

Thank you.

0

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:35

  This post is more than two 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.
• 

  Riley Clement

  • Gurobi Staff

  October 30, 2023 02:35 Edited

  Hi Akbar,

  The issue here relates to programming in Python, in general, rather than being specific to Gurobi.  You can find a good explanation in the YouTube video: https://www.youtube.com/watch?v=CqvZ3vGoGs0

  So, "Model" is a thing which comes from the gurobipy package, so you need to tell Python this information.  You can achieve this with the following alternatives:

  from gurobipy import Model
  
  m = Model()

  import gurobipy
  
  m = gurobipy.Model()

  import gurobipy as gp
  
  m = gp.Model()

  Note that the last option is the preferred style.

  I also suggest moving your import statements to the top of your file, and taking advantage of our Model.addVars function:

  import gurobipy as gp
  from gurobipy import GRB
  
  def UPMSet(jobs,machines,workers,activities,oprttime,machining,moving,B):
      m = gp.Model()
      x = m.addVars(
          workers, machines, activities, len(jobs), machines, activities, jobs,
          vtype="B",
      )
      ...

  - Riley

   

   

   

  0

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