What Is a Working-Hour Tick in Optimization? EDGEBIC Definition

A working-hour tick is the time unit the exact optimizer measures in: one hundredth of an hour, or 36 seconds. The exact solver places every time on a single global calendar with nights, weekends, and whole-day holidays compressed out, and it represents all times as whole-number counts of ticks rather than floating-point hours. Durations round up to whole ticks so the model never under-books time. It is the ruler the optimizer uses to measure the whole plant week, marked in 36-second increments with the closed hours cut out.

This entry is part of the EDGEBIC by User Solutions glossary series; for the broader vocabulary of planning, see the manufacturing glossary. For how the optimizer starts from the existing plan, see what is a warm start.

How a Working-Hour Tick Works

The exact optimizer is a mathematical solver, and solvers reason best over whole numbers. Feeding it decimal hours would invite the rounding errors that plague floating-point arithmetic. So the optimizer converts time into a fixed, small unit and counts it: the working-hour tick.

A tick is one hundredth of an hour, 36 seconds. Every start, end, and duration in the model becomes an integer number of ticks. That unit is fine enough that realistic setup and run times map onto it cleanly, and coarse enough to keep the model compact and fast to solve.

The tick ruler is laid on a single global calendar, but not an ordinary one. Nights, weekends, and whole-day holidays are compressed out, so the ruler only counts time the plant can actually work. The optimizer never wastes effort reasoning about hours when no machine is running; a job spanning a weekend is measured only by the working ticks around it.

One safety rule governs conversion: durations ceil to whole ticks. When a step's time does not land exactly on a tick boundary, the model rounds up, reserving at least as much time as the step needs and never less. That way the optimizer's plan is always physically achievable rather than quietly over-promising.

A Concrete Example

Imagine measuring the whole plant's week with one ruler. An ordinary ruler marked in hours would carry the nights and weekends as long empty stretches the plant cannot use, and its decimal marks would blur under the solver's arithmetic.

The optimizer's ruler is different. It is marked in 36-second increments, so a 6-minute setup is exactly 10 ticks and a two-hour run is 200 ticks, each an exact whole number the solver reasons about without rounding drift. And the closed hours are cut out of the ruler entirely: the marks jump from Friday's last working tick straight to Monday's first, so the weekend simply is not on the ruler. The optimizer measures only the time that can hold work, in a unit fine enough to be honest and integral enough to be exact.

How EDGEBIC Uses It

The working-hour tick is the time model of the exact optimizer:

• All model times are integers, whole counts of ticks, which keeps the solver's arithmetic exact and its results deterministic run to run.
• The calendar is a single global timeline with nights, weekends, and whole-day holidays compressed out, so the model only reasons about schedulable time.
• Durations ceil to whole ticks, reserving at least as much time as a step needs, so the optimizer never under-books and its plan stays physically achievable.

The tick is how the exact optimizer represents time internally; the plan it improves comes in as a warm start, the existing greedy schedule handed to the solver as its starting point. To run the optimizer and read what it produced, see how to run and read an optimization.