Form a new variable from the subset of original variable (maximum values)

Answered

Luka Herc

February 07, 2023 08:57 Edited

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Hello,

I have the code that outputs achieved prices for multiple generators for each hour(period) and year in modelling horizon.

Is there a way to form a new variable (meritorder[period, year]) that will include only subset of the original variable (gencosth[genco, period, year]), but include only the maximum values for each hour and year?

Pseudocode would look something like this:

merit_order =ucp.addConstrs((gencosth[genco, period, year] for genco in units)==
                                        meritorder[period, year]                                                                         
                                            for period in periods for year in years)

Related to

• Python
• General Constraints

0

• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:49

  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.
• 

  Jonasz Staszek

  • Community Moderator

  February 07, 2023 10:05 Edited

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  Hi Luka,

  you may be after generating one variable for each subset for which you look for a maximum and then adding a max general constraint.

  I would try something along the lines of:

  meritorder = gp.tupledict()
  for period in periods:
      for year in years:
          meritorder[period, year] = ucp.addVar(vtype="C", name=f"meritorder_{period}_{year}") # I assume the variables are continuous
          ucp.addConstr(meritorder[period, year] == gp.max_([gencosth[genco, period, year] for genco in units]))

  Hope this helps.

  Best regards
  Jonasz

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• 

  Luka Herc

  February 07, 2023 09:53

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  Thank you very much! It seams to work.

  With the code you presented, I got an error "NameError: name 'max_' is not defined".

  Therefore, I had to call the "max_()" function via Gurobipy and the final part of the script is:

  meritorder = gp.tupledict()
  for period in periods:
      for year in years:
          meritorder[period, year] = ucp.addVar(vtype="C", name=f"meritorder_{period}_{year}") 
          ucp.addConstr(meritorder[period, year] == gp.max_([gencosth[genco, period, year] for genco in units]))
          

  Best regards,

  Luka

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• 

  Jonasz Staszek

  • Community Moderator

  February 07, 2023 10:04

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  Thanks for pointing this out - my code was meant to be a rough guideline. Now, we have a correct piece of code for future reference.

  Best regards
  Jonasz

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