Examples
Examples
Try the starting example
- Jobs: name, release time, duration, due time, setup group
- A,0,4,10,repair B,0,1,2,adjust C,0,2,5,repair
- Setup changes: from group or start, to group, duration; absent pairs mean zero
- start,repair,1 repair,adjust,1 adjust,repair,1
- Selected rule: input, SPT or EDD
- input
- Selected job sequence
- A, B, C
- Selected-rule last finish
- 10
- Selected-rule mean release-to-finish time
- 7.333333
- Selected-rule total tardiness
- 10
- Selected-rule setup time
- 3
- Finish and total tardiness under all three rules
- input: 10, 10; SPT: 8, 0; EDD: 8, 0
Try another scenario
- Jobs: name, release time, duration, due time, setup group
- A,0,4,10,repair B,0,1,2,adjust C,0,2,5,repair
- Setup changes: from group or start, to group, duration; absent pairs mean zero
- start,repair,1 repair,adjust,1 adjust,repair,1
- Selected rule: input, SPT or EDD
- SPT
- Selected job sequence
- B, C, A
- Selected-rule last finish
- 8
- Selected-rule mean release-to-finish time
- 4.333333
- Selected-rule total tardiness
- 0
- Selected-rule setup time
- 1
- Finish and total tardiness under all three rules
- input: 10, 10; SPT: 8, 0; EDD: 8, 0
Calculation method
Calculation method
Selected job sequence
At each decision choose available jobs by input order, shortest processing time, or earliest due date; ties use input order.
Selected-rule last finish
Simulate one mechanic with no preemption; setup occurs before each selected job.
Selected-rule mean release-to-finish time
Average(end−release), including setup and waiting.
Selected-rule total tardiness
Sum max(0,end−due).
Selected-rule setup time
Sum entered directed group-change setup times; missing pairs are explicitly zero.
Finish and total tardiness under all three rules
Run all three dispatch rules on the same releases, durations, deadlines and setup table.
Symbols and units
- a
- Jobs: name, release time, duration, due time, setup group
- b
- Setup changes: from group or start, to group, duration; absent pairs mean zero
- c
- Selected rule: input, SPT or EDD
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- A deterministic single-mechanic dispatch comparison with at most fifty jobs. SPT and EDD are dispatch heuristics when releases and setup changes exist; no global optimum, staffing recommendation or service-time estimate is claimed.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
OpenStax: arithmetic model background ↗
Background reading; this does not imply endorsement or independent review of SumFizz.