Modeling tips

This page contains tips for modeling business rules in the API.

Ports

How do I restrict vessel class compatibility at certain ports due to draft or international laws?

Specify costs in the corresponding Port only for allowed vessel class.

How do I forbid transshipment at certain ports?

Set the transshipment cost to infinite (or a very large value).

Demands

What can be included in the freight rate?

Freight rate can include any relevant metric for the liner shipping company such as economic value, environmental impact, customer satisfaction. Regarding the latter, a penalty for not serving demand should be added to the freight rate.

Can the model handle demands with same origin-demand pairs but different specifications?

Yes.

Leg candidates

What advantage do leg candidates offer compared to actual port connections?

Leg candidates of the API support modeling of:

  • Multiple trajectories between the same two ports
  • Arbitrary cost functions for different velocities on the same trajectory
  • Vessel class specific costs
  • Vessel class restrictions (due to draft for canals or international laws)

Most importantly, leg candidates define an unambiguous definition of port connections. This is not the case with physical port connections which allow for many interpretations in possible operations (cost, idle time, …).