Using Simquence

The app's own Guide, shortened. The full version ships in the app, under the i button at the right of the toolbar.

Your first run, in six steps

1. Examples menu, then Checkout. Run flashes twice to say it is ready.
2. Leave Runs at 200 and Seed at 1.
3. Press Run.
4. Read Summary: the percentiles of the makespan, which is how long the whole piece of work took.
5. Read Critical path: the chain of work that actually held the run up.
6. Press the chart button in the middle of the toolbar for Distributions, then look at the shape rather than any one number.

That is the whole loop. Everything else is a variation on it.

What each panel means is on Reading the output.

Change one thing, run it again

1. Press Edit. The composer opens with the loaded model already in it.
2. Change one thing. Raising a context's concurrency from 1 to 2 is the clearest first experiment.
3. Export + Load Into Main UI, then Run again with the same seed.
4. Compare the percentiles and the dominant path against what you had.

One change at a time. Two changes and a different answer tells you nothing about which one did it.

Writing a model from nothing

Press Compose for a new model and work down System, Contexts, Tasks and Wiring in order, because each uses the one before it. Then Validate and Export.

Choosing the settings

• Runs. 200 is enough to see the shape and compare two structures. To say anything about p99, think in thousands.
• Seed. Same model and seed, same answer, every time. Hold it steady to compare structures, then change it to check the difference was not one lucky draw.
• Concurrency. How many things genuinely happen at once. 1 serialises everything, which is what a single database connection or UI thread is.
• Distribution. Fixed only when the duration truly does not vary; Normal for symmetric variation; Lognormal for IO, network or contention, where normal comes out far too optimistic at p99.
• Delays on wiring. Debounces, backoffs, poll intervals. They frequently own the median while everyone is looking at the database.
• Stress multiplier. Every duration multiplied: what happens when everything is twice as slow?

Simquence tells you what a model does, not whether the model is right. It makes an argument checkable; it does not spare you having one.