Constraints for Optimization
Use
The optimizer takes into account constraints when assigning orders and deliveries to vehicle resources. You can differentiate between hard and soft constraints:
The optimizer always adheres to hard constraints.
You model soft constraints using penalty costs, for example, delay costs that are part of the total costs .
The optimizer minimizes the total costs in the optimization run while adhering to the hard constraints. By appropriately weighting the penalty costs in the total costs, you can influence the priority of adhering to the soft constraints. If, for example, you give a greater weighting to the penalty costs, the optimizer’s main aim is to adhere to the constraints. If, however, you give a lesser weighting to the penalty costs, the optimizer first deals with other parts of the costs (for example, minimum number of vehicle resources) and accepts the violation of the soft constraints.
Example
Hard constraint: Loading capacities of a vehicle resource. The optimizer can only schedule orders within existing transportation capacities.
Soft constraint: Requirement dates of sales orders. The optimizer can also schedule a sales order after the requested delivery date. In this case, delay costs are incurred.
Features
The following table shows the planning data that the optimizer considers as constraints:
Planning Data |
Constraint |
Comment |
|---|---|---|
Loading capacities |
Hard |
|
Loading resources (inbound/outbound) and opening times |
Hard |
|
Hard |
||
Pickup |
Soft |
The optimizer can also schedule the pickup of the order before or after the material availability date. In this case, earliness or delay costs are incurred. You can define tolerances for the premature or delayed pickup without penalty costs (see Definition of Windows ). |
Hard |
The optimizer can only schedule the pickup for the material availability date. You can define tolerances within which a premature or delayed pickup is allowed (see Definition of Windows ). |
|
Soft and hard |
A combination of the options described above |
|
Delivery |
Soft |
The optimizer can also schedule the delivery of the order before or after the requested delivery date. In this case, earliness or delay costs are incurred. You can define tolerances for the premature or delayed delivery without penalty costs (see Definition of Windows ). |
Hard |
The optimizer can only schedule the delivery for the requested delivery date. You can define tolerances within which a premature or delayed delivery is allowed (see Definition of Windows ). |
|
Soft and hard |
A combination of the options described above |
|
Journey to depot for own means of transport |
Hard |
|
Loading and unloading durations |
Hard |
|
Schedules of means of transport (trains, ships, airplanes, and trucks) |
Hard |
|
Minimum goods wait timeat the location |
Hard |
Only relevant for cross-docking |
Maximum goods wait timeat the location |
Hard |
Only relevant for cross-docking |
Distance traveled (for each vehicle resource) |
Soft |
The optimizer attempts to schedule the shortest distance possible. |
Hard |
The distance must not be greater than the value defined in the cost profile. |
|
Soft and hard |
A combination of the options described above |
|
Journey duration (for each vehicle resource) |
Soft |
The optimizer attempts to schedule the shortest duration possible. |
Hard |
The duration must not be greater than the value defined in the cost profile. |
|
Soft and hard |
A combination of the options described above |
|
Number of stop-offs (for each vehicle resource) |
Soft |
The optimizer attempts to schedule as few stop-off as possible. |
Hard |
The number of stop-offs must not be greater than the value defined in the cost profile. |
|
Soft and hard |
A combination of the options described above |
|
Wait time |
Hard |
|
Maximum length of stay |
Hard |
The optimizer does not take into account the maximum length of stay for trailers. |
Hard |
||
Compartment capacities |
Hard |
|
Capacities of means-of-transport combinations |
Hard |