The requirements for construction workers at a construction site during a period of six months are known. Transfers from other sites to this one are possible on the first day of every month and at the end of every month workers may leave to other sites. Transfer, understaffing, and overstaffing incur known costs per month per post. Overtime work is limited to 25 of the hours worked normally. The monthly arrivals and departures are limited. Three workers are already present on site at the beginning of the planning period and that three workers need to remain on-site at the end. Which are the number of arrivals and departures every month to minimize the total cost?

Further explanation of this example: 'Applications of optimization with Xpress-MP', Section 14.6 'Planning the personnel at a construction site' (i6build.mos)

! Data file for `persplan.mos'

REQ: [4 6 7 4 6 2]

CARR:   100
CLEAVE: 160
COVER:  200
CUNDER: 200

NSTART: 3
NFINAL: 3

NAMES: ["Mar" "Apr" "May" "Jun" "Jul" "Aug"]