2.8 Global Parameters

2.8.1 Iterations

The number of iterations the optimiser will run for. Each iteration may result in an improved solution and hence a higher number of iterations increases the probability of finding a better solution. This comes at the cost of increasing the duration the optimiser will run for.

2.8.2 Batched Loads

Batched loads is a scheduling constraint that enforces a strict “Pickup - Delivery” cycle where once a vehicle begins making deliveries, it cannot pick up new orders until it has delivered all of its current orders. (See Section  2.19 for further information.)

2.8.3 Colocated Pickups

Colocated pickups refers to a scheduling constraint that all orders in a load must have come from the same location.

2.8.4 Sticky Deliveries

If sticky deliveries are enabled then the optimiser will attempt to assign all of the orders being delivered to an individual location to the same vehicle. The intention of this is to reduce the number of different vehicles that make deliveries at a location.

2.8.5 Scaling Factors

A scaling factor can be applied to speeds, costs, weights and volumes in the scenario. This allows the user to increase the effect that a particular variable has on the optimiser. A value of 0 means that no scaling is applied. The scaling factors include speed scale, cost scale, weight scale and volume scale.

2.8.6 Geofencing

The optimiser can be restricted to only consider orders and vehicles that are located within a specific geographic area. This area is called a geofence and it takes the form of a bounding box that is defined by the latitudes of its southern and northern boundaries and by the longitudes of its western and eastern boundaries.

The geofence can operate in one of two modes: hard and soft.

If the geofence is in hard mode then the optimiser will report an error for any order that has pickup or delivery locations outside the geofence. It will also report an error for any vehicle that has start or finish locations outside of the geofence. In the event of such errors being detected, optimisation will not proceed.

If the geofence is in soft mode then the optimiser will not assign any order whose pickup or delivery location is outside the geofence. It will not use any vehicle whose start or finish location is outside the geofence. In this mode optimisation will proceed using orders and vehicles that are within the geofence.

2.8.7 Maximum Neighbourhood Size

The maximum size of the neighbourhood for the optimiser. At each iteration of the optimiser, the solution is unpacked and changed to find a new solution with the neighbourhood being the amount to unpack. Smaller neighbourhoods are quicker to change but may result in worse quality solutions, while larger neighbourhoods require a longer running time but may lead to better quality solutions. Note that the maximum neighbourhood size must be at least ten.

2.8.8 Preferred-Vehicle Rewards

If preferred vehicles are specified for an order, then there are three types of rewards that can be specified.

  1. Preferred Vehicle Fixed Reward

    This is a fixed reward for assigning the order to one of its preferred vehicles.

  2. Preferred-Vehicle Weight Reward

    This reward is multiplied by the weight of the order if it is assigned to one of its preferred vehicles. It can be used to give a higher priority to assigning heavier orders to their preferred vehicles.

  3. Preferred-Vehicle Volume Reward

    This reward is multiplied by the volume of the order if it is assigned to one of its preferred vehicles. It can be used to give a higher priority to assigning larger orders to their preferred vehicles.