Fix a variable and evaluate the Objective function value

Answered

Azi

• February 24, 2020 18:50

Hello,

 

Is there any efficient way to fix a variable at a specific value? I want to give the solution for a variable to the model as input and see what will be the value of objective function for that specific point. The only way came to my thoughts is to add a new constraint that makes that variable equal to specific value but this increases my computational time as the number of constraints are larger now.  This is part of my model and if that helps, variable w is the order of visited nodes. I want to be able to change the order by setting the value of w at specific values. The whole model solves to optimal in 60 seconds but when I add those new constraints at the end in the following screen shot, it takes much longer to solve. Any help is much appreciated.

0

• 

  Chags

  • February 26, 2020 23:22

  

  

  

  I usually make this by change the variable bounds

  try:

  w[(7,1)].ub = 2
  ​
  w[(7,1)].lb = 2

  0
• 

  Azi

  • March 03, 2020 20:44

  

  

  

  Thank you very much. 

   

  Azadeh

   

  0

Please sign in to leave a comment.