Seek help about formulation of the constraints

Awaiting user input

YUNFAN KANG

February 12, 2022 00:45

• 
• 

I want to write a MIP solver for the max-p-region problem: https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1467-9787.2011.00743.x 

I do not know how I can add this constraint (constraint (4) on page 8, where Ni is a set of integers. Could someone please give me a hint about how to write the addConstrs() for this constraint?

0

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 16, 2025 23:43

  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

  February 12, 2022 09:10

  • 
  • 
  • 

  Hi Yunfan,

  I assume you use Python API.

  Based on your inputs, I would imagine the following code to work:

  import gurobipy as gp
  
  model = gp.Model()
  
  # define K, C, I and x
  for k in K:
      for c in C:
          for i in I:
              m.addLConstr(
                  x[k, c, i] <= gp.quicksum(x[k, c - 1, j] for j in N[i]),
                  name=f"c_{k}_{c}_{i}",
              )
  
  # alternatively
  m.addConstrs(
      (
          x[k, c, i] <= gp.quicksum(x[k, c - 1, j] for j in N[i])
          for k in K
          for c in C
          for i in I
      ),
      name="c",
  )

   

  0

Post is closed for comments.