Factors

A factor is a setting you allow PM Optimizer to change while it searches. Each factor names one thing in your model and the values to try for it.

The factors table

Each row is one factor and shows what it changes, which setting, its type, and the range or list of values to try. The count in the corner, the possible combinations, multiplies the choices together so you can see how big the experiment is before you run it. Clear the checkbox at the start of a row to hold that factor out without deleting it; its setup stays exactly as you left it.

Factors come in a few types:

• Range: a number swept between a low and a high value, such as a capacity from 5 to 15 in steps of 5.
• Options: a choice from a list, such as a queue’s priority rule (first in first out, last in first out, or by attribute).
• On or Off: something the experiment turns on in some runs and off in others.
• Model change: a change to the shape of the model, such as a new resource that exists in some runs and not in others.
• Logic: a value inside your own logic, such as a variable’s starting value.

Add a factor

Add Factor opens a picker that lists everything in your model you can change, grouped by the kind of object.

• Entities: carrying capacity and costs.
• Activities: capacity, processing time, shift, and costs.
• Queues: capacity, priority rule, and costs.
• Resources: quantity, availability percent, shift, and costs.
• Gates: how the gate releases and how long its window holds.
• Routes and connections: move time, split percentages, and which resource works at which activity.
• Arrivals: quantity, spacing, demand percent, and on or off.
• Inventory: reorder level and quantity, lead time, and costs.
• Variables: a variable’s initial value.

A final group, Add something new, tries things your model does not have yet: Add a resource (a new resource that exists in some runs or all), Add a backup connection (with or without a backup resource at an activity), Grow a resource group (add a member to an existing group), and Try different shifts (compare two or more shift patterns).

Everything you can change is listed. An item shown in grey cannot be a factor, with a short note on the row explaining why, so you are never left guessing what is missing.

Keep the list short

Every factor you add multiplies the number of runs, so start with the few settings you think matter and set tight, realistic ranges. If you are not sure which settings matter, use the screening panel on the Define step, right below the factors table: it runs a handful of cheap probe runs and tells you which factors actually move your result, so you can hold the rest out before the real experiment starts. The designs article covers how it works.