Time Expression

The Time Expression window writes the time and distribution expressions that drive your model, such as an activity’s processing time or a route’s move time. Open it from any time field and it builds a valid expression for you, so you do not have to remember the syntax. It has three tabs.

You can also open it on its own, with no field waiting for the answer, from the Tools menu or with Ctrl+Shift+F. Opened that way it starts on Fit Data to Distribution, and its main button reads Copy rather than Apply: it puts the finished expression on the clipboard, ready to paste wherever you need it.

Fit data to distribution

Have real timing data? Paste or import it, one number per line or separated by commas or spaces, and choose Analyze. ProcessModel fits every distribution it knows to your data, ranks them by how well each one fits, and hands you the best-fit expression, for example Weibull(4.732, 22.293).

Earlier versions bundled a separate tool called Stat::Fit for this. ProcessModel now has its own built-in fitting, so nothing extra is needed.

Build distribution

No data yet? Pick a distribution type and enter its parameters. The window shows a live preview of the expression and its shape as you type, for example T(2, 5, 10) for a triangular distribution. You can also set lower and upper limits so sampled values stay within a range.

Time table

Use a time table when the value changes by time of day or shift, such as a service time that is shorter in the morning and longer in the afternoon. The expression then evaluates against the simulation clock as the model runs.

Applying and reusing

Choose Apply to validate the expression and drop it into the field. You can Save a distribution you built or fitted and Open it again later, and you can generate a sample of values to check the shape before you commit to it.