Discrete Bat Algorithm for Optimal Problem of Permutation Flow Shop Scheduling

Algorithm 2

The pseudocode of NEH and NEH1.

    Compute the total processing time for each job on m machine;

    Generate a sequence by sorting the jobs in non-increasing order according to

    the total processing time;

    The first job is taken. ;

for   : 

          /*  The  implemented operations of NEH and NEH1 is different, the NEH insert a job into all possible

                 positions of , but the NEH1 only insert a job into the front and rear of . The other operations are

                consistent both NEH and NEH1.  */

         Take job form   and insert into all possible positions of ;  //  Operation of NEH

         Take job form   and insert into the front and rear of ;  //  Operation of NEH1

         Evaluate the new sequence ;

        Select the with lowest objective value;

endfor

    return ;