No consecutive Day/Night shifts

Answered

James Absolom

• December 20, 2022 21:24

Im working off of example "workforce5" in python and was wondering if there was a constaint that could be added to make it so that workers can't do consecutive shifts. This is because our model has day/ night shifts and the workers shouldnt work a day after a night or vice versa.

Any help would be appreciated :)

Related to

• Python

1

• 

  Maliheh Aramon

  Gurobi Staff

  • December 21, 2022 01:22

  Hi James, 

  Let us define the set \(S\), \(S = \{(s_i, s_j) | s_i ~\mbox{and} ~s_j ~ \mbox{are consecutive shifts}\}\), containing tuples of consecutive shifts. Given \(x_{ws}\) is a binary decision variable being equal to 1 if worker \(w\) is assigned to shift \(s\), the constraint below ensures worker \(w\) cannot be assigned to consecutive shifts . 

  \[x_{ws_i} + x_{ws_j} \leq 1, ~~ (s_i, s_j) \in S, ~ w \in W\]

  The code snippet below shows how to implement this constraint in workforce5.py example.

  consecutiveShifts = [
      ("Mon1", "Mon8"),
      ("Mon8", "Tue2"),
      ("Tue2", "Tue9"),
      ("Tue9", "Wed3"),
      ("Wed3", "Wed10"),
      ("Wed10", "Thu4"),
      ("Thu4", "Thu11"),
      ("Thu11", "Fri5"),
      ("Fri5", "Fri12"),
      ("Fri12", "Sat6"),
      ("Sat6", "Sat13"),
      ("Sat13", "Sun7"),
      ("Sun7", "Sun14"),
      ("Sun14", "Mon1"),
  ]
  
  # Constraint: each worker is not assigned to consecutive shifts
  model.addConstrs(
       (x[w, s1] + x[w, s2] <= 1 for s1, s2 in consecutiveShifts for w in Workers),
       name="noConsecutiveShifts",
  )

   

  Best regards,

  Maliheh

  1
• 

  James Absolom

  • December 21, 2022 11:33

  

  

  

  Thankyou very much, I didnt think of that :D

   

  0

Please sign in to leave a comment.