Variable Neighborhood Search for Parallel Machines Scheduling Problem with Step Deteriorating Jobs

Algorithm 2

Procedure of neighborhood structure NSS₁.

Procedure: 𝑁𝑆𝑆₁

improvement = yes

while (improvement = yes) do

   improvement = no

   𝑖=1

 while  𝑖≤𝑛  do    (𝑛 is the number of jobs)

  select randomly one job 𝑝 without repletion from the current solution 𝑥

   𝑥^  = swap job i and job p on their positions.

   if  Z(𝑥^) < Z(x) do

    𝑥=𝑥^

    𝑖=𝑛

    improvement = yes

   end  if

   𝑖=𝑖+1

 end  while

end  while