Cannot understand getBackwardTransportTime / getBackwardTransportCost

Hello all,

I’m having a little trouble understanding getBackwardTransportTime vs. getTransportTime, although I’ve read @jie31best’s reply, and I’d appreciate a little help:

Could someone please explain, in layman’s terms, what are the differences between getTransportTime / getBackwardTransportTime, and getTransportCost / getBackwardTransportCost?

Initially, I’ve wrongfully thought that this is used in case of an asymmetrical time / distance matrix, e.g. I thought that getTransportTime is used to check time from A to B and getBackwardTransportTime is used to check time from B to A.

How does implementing AbstractForwardVehicleRoutingTransportCosts (e.g. getTransportTime = getBackwardTransportTime) influence a solution?

Thank you for any pointers,