for   = 0 to   do
 pool of solutions   Diversification()
for     do
   :=     Improvement
     Reference Set Update
end for
repeat
  pool of subsets   Subset Generation
  for     do
      Solution Combination
    ′}    Improvement( ′)
      Reference Set Update
       end for
      until   remains the same
  end for
Algorithm 1: Scatter search.