Is it possible to make nullable chained variables?

Question

I’m working on a VRP problem with optaplanner where not every customer needs to be visited. I know that genuine variable can be configured as nullable in optaplanner. So I wonder what should I do on chained variables like customers ?

Answer 1

This is a limitation of chained variables to at least the current version 7.18. We have ideas on how to support this in a future version some day.

The common workaround is to create a "dummy vehicle" and adjust all constraints to ignore visits of the dummy vehicle, so they don't affect the score. Any visit assigned to the dummy vehicle is basically unassigned.