The solver will try to find the best values to assign to each shift. In order to do this, constraints are used to
determine how good a solution is. These constraints represent different numbers used to score the solution. These
constraints are prioritised by being either HARD, MEDIUM or SOFT. All improvements in HARD constraints trump any
deterioration in MEDIUM or SOFT constraints. All improvements in MEDIUM constraints trump any deterioration in SOFT
constraints.
In this table is a summary of all constraints and what they mean, along with the priority level the solver assigns to
each. These priority levels are fixed internally by the solver and are not currently configurable through the request.
Name
Level
Description
Total Demand
HARD
The total required demand must be met (only relevant in fixed mode).
Max available resources
HARD
Only the maximum number of available resources for every resource type can be used.
Min Time Between Shift Start
HARD
Two shifts with different start times cannot have start times closer to each other than the minimum allowed time specified (optionally) by the user.
Under demand
MEDIUM
For every demand time block, the supply that is less than the demand must be minimised.
Over demand
MEDIUM
For every demand time block, the supply that is more than the demand must be minimised.
Under Demand Cumulative
MEDIUM
Only relevant in flexible mode. For every demand time block, the cumulative supply that is less than the demand’s min value must be minimised.
Time Wasted Cumulative
MEDIUM
Only relevant in flexible mode. Penalises cumulative supply that exceeds the demand’s max value (work that would be wasted).
As Late As Possible
SOFT
Only relevant in flexible mode. When a demand’s priorityRule is ALAP, try to plan shifts as late as possible while respecting the Over Demand and Under Demand constraints.
As Soon As Possible
SOFT
Only relevant in flexible mode. When a demand’s priorityRule is ASAP, try to plan shifts as soon as possible while respecting the Over Demand and Under Demand constraints.
