gurobipy.GurobiError: Name too long (maximum name length is 255 characters (python)

回答済み

Chao Guo

• 2024年05月06日 12:48

A similar issue to the post in https://support.gurobi.com/hc/en-us/community/posts/8827103170065-Gurobipy-addMConstr-raises-GurobiError-Name-too-long-when-passing-list-of-names?page=1#community_comment_24815782077969  (gurobipy.GurobiError: Name too long (maximum name length is 255 characters)), which is occurred when adding variables by calling model.addVars().

I figured out the reason for this after printing the name of another variable with four indices, as follows (here, I replaced the original text with multiple "x" to hide information):

x[<xxxxxxxxx.xxxxxxxxxx.xxxxxxxx object at 0x000002B85AD43750>,<xxxxxxx.xxxxxxxxx.xxxxxxxx object at 0x000002B85B07A7D0>, xxxxxx.XXXXX,<xxxxxxx.xxxxxxx.xxxxxxx object at 0x000002B85B07AA10>]

The addVars method automatically gives the name indices as the full address information of each corresponding object, resulting long name.

Is there any way to change the indices into a self-defined string?

Best regards

0

• 

  Riley Clement

  Gurobi Staff

  • 2024年05月06日 13:22

  Hi Chao,

  One option is to supply all the names as a list to the addVars function.  As and example, instead of

  A = ["mylongindexname_a", "mylongindexname_b", "mylongindexname_c"]
  B = [1,2]
  
  x = m.addVars(A,B, name="my_var")

  use

  import itertools
  
  def make_name(key):
      indexA, indexB = key
      return f"my_var_{indexA.split('_')[1]}_{indexB}"
  
  names = [make_name(key) for key in itertools.product(A,B)]
  x = m.addVars(itertools.product(A,B), name=names)

  You will need to define your make_name function to map the keys to your desired (and simplified) name structure.

  - Riley

  0
• 

  Chao Guo

  • 2024年05月07日 03:21

  

  

  

  Dear Riley,

   

  Thank you so much for your help! My problem is perfectly solved.

   

  -Chao

  0

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