Objective Weights

When defining solver settings, you can define objective weights allowing you to optimize on specific objectives. A weight of 0 means that the solver will not consider the objective. The sum of the weights should be greater than 0 so at least one objective should have a value. This is expressed as a number not a percentage.

The objectives that you can specify are as follows:

• Span - This objective is the difference between the start of the earliest batch in the selection and the end of the latest scheduled batch in the selection. Setting this allows you to minimize the overall time span between the first and last batch. Note that if batches are locked and thus cannot be scheduled, then they are not taken into account in this objective.
• Setup - This objective is the duration of the setup segments in the batches selected.
• Setup cost - This objective is the sum of the setup costs of the selected batches and non-selected batches on the scheduled resources.
• Changeover - This objective is the total duration of the changeover segments in the batches selected.
• Changeover cost - This objective is the sum of the changeover costs of the selected batches and non-selected batches on the scheduled resources.
• Dist to earliest start - This field is visible only if the selected scheduling strategy in the Schedule batches list box is Earliest start time. This field refers to the Distance to the earliest start and is an absolute value.
• Dist to latest end - This field is visible only if the selected scheduling strategy in the Schedule batches list box is Just in time (JIT). This field refers to the Distance to the latest end and is an absolute value.
• Slack - This objective is waiting time. If a batch is ready to begin outflow but has not started because the process is not ready, there is slack. This waiting time is not programmed in, but happens because of other factors.
•  Dist to start work area - This field is visible only if the selected scheduling strategy in the Schedule batches list box is As soon as possible (ASAP). If set, it minimizes the summed start time of all batches and moves the batches as far left as possible. This is similar to schedule as soon as possible, but can be optimized since it is an objective.
• Dist to end work area - This field is visible only if the selected scheduling strategy in the Schedule batches list box is Just in time. This objective is the sum of distances between each batch and the scheduling boundary. Here distance is defined linearly, as the difference between the start or end of a batch and the start or end of the Horizon (or work area). The result of distance to earliest end is that batches are "pulled" toward the right; that is, solutions where the sum (or "average") of starts is smallest are favored with ASAP, but with JIT solutions with largest end times are preferred because they are closer to the end of horizon. This is similar to schedule just in time, but can be optimized since it is an objective.