Forming a model inside a function

Answered

Iason Liagkas

December 21, 2023 00:38

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Hello Guys, I am trying to code a Python function to build a model inside. The name of the function is SP_define. The function returns the model only. I run the below code. When I print the model I get the number of constraints and vars as you can see. But When I optimize the objective function gets the value of 0 and all the ranges are 0. 

Meanwhile, If I run the internal code of the function that makes the model as autonomous lines of code I get a different optimization result when I optimize:

Do you have any idea of what could be going wrong?  I am using the line SPmodel.update() before the return SPmodel.

Kind regards
Iason

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  Riley Clement

  • Gurobi Staff

  December 21, 2023 00:42

  Hi Iason,

  I think we'll need to see some code... both the function where you create the model, and where you call it.

  - Riley

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  Iason Liagkas

  December 21, 2023 01:07

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  Hi Riley I found out my bug. Instead of writing SPmodel.optimize() I should write a subproblem.optimize() since the SPmodel is lying inside the function, while the subproblem is the variable that the function passes the model. Sorry for the confusion.
  
  Kind regards 
  Iason

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  Riley Clement

  • Gurobi Staff

  December 21, 2023 01:13

  No problem, well done on spotting it.

  - Riley

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