Description of the Files of the VRPLIB Instances

The data format used in VRPLIB [Reinelt 1991] files is an extension of the TSPLIB data format for capacitated vehicle routing problems; see G. Reinelt: "TSPLIB – A Traveling Salesman Problem Library", ORSA Journal on Computing 3 (1991), 376–384.

A TSPLIB file contains a problem specification part that indicates the type of problem (TSP – symmetric traveling salesman problem, ATSP – asymmetric traveling salesman problem, CVRP – capacitated vehicle routing problem) and a data part that contains the data; both parts are not separate sections in a file but assigned by keywords.

Extensions of the specification part

• Type:
  • CVRPP – for additional pickups and volume capacities
  • CVRPTW – for additional time windows and standing times
  • CVRPPTW – for both CVRPP and CVRPTW
• COORDx_SCALE: to be used to assign the factor 1.2 as ratio direct line / distance by motorway; the effect of this specification is that coordinates are multiplied with a factor.
• CAPACITY_VOL: new keyword for the volume capacity of trucks in cubic meters.

Extensions of the data part

• Coordinate section, giving x and y coordinates of nodes by node identification numbers starting at 1:
  NODE_COORD_SECTION
<id> <x-coord> <y-coord>
• Demand section, giving demands <dem> at nodes <id>:
  DEMAND_SECTION
<id> <dem>
• Depot section, giving a list of possible depot nodes <dep_id> and terminated by -1:
  DEPOT_SECTION
<dep_id>
• The data part is terminated by EOF.
• Additional sections are, according to problem:
  • TIME_WINDOW_SECTION
<id> <begin_hh>:<begin_mm> <end_hh>:<end_mm>
    • <id> – identification number of node
    • <begin_hh>:<begin_mm> – begin of time window, time given in hours and minutes
    • <end_hh>:<end_mm> – end of time window
  • STAND_TIME_SECTION
<id> <time> – standing time in minutes at node <i>
  • PICKUP_SECTION
<id> <weight> <vol> – return load present at node <id> with weight in kg and volume in cubic meters
  • DEMAND_SECTION
<id> <weight> <vol> – as in PICKUP_SECTION