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

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  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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