A company has received an order for three types of wallpapers. Every paper type is produced as a continuous roll of paper that passes through several machines, each printing a different color. The order in which the papers are run through the machines depends on the design of the paper. The processing times differ depending on the surface that needs to be printed. Knowing that every machine can only process one wallpaper at a time and that a paper cannot be processed by several machines simultaneously, how should the paper printing be scheduled on the machines in order to finish the order as early as possible?

Further explanation of this example: 'Applications of optimization with Xpress-MP', Section 7.3 'Job shop scheduling' (b3jobshop.mos)

! Datafile for 'jobshop.mos'

DUR: [(1 1) 45 (1 2) 20 (1 3) 12
               (2 2) 10 (2 3) 17 
      (3 1) 10 (3 2) 34 (3 3) 28]

NUMT: [2 3 3]

SEQ: [(1 1) 1 3
      (2 1) 2 1 3
      (3 1) 3 1 2]

NUMD: [3 2 3]

DISJ: [(1 1) 1 2 3
       (2 1) 2 3
       (3 1) 1 2 3]
       
COLOR: ["Blue" "Green" "Yellow"]