How much of a digital-twin run should be thrown away because it started in the wrong state?

What it found

A twin started from an empty queue or a nominal sensor value is biased at first. For AR(1) output the bias and variance of the run mean are exact (0.300 vs 0.300 simulated at φ=0.9, n=100), and the MSE-optimal warm-up is about one relaxation time 1/(1−φ) with a gain of at most 1.5× and 1.03× once n is about a hundred relaxation times. An M/M/1 instrument started empty underestimates the mean wait by 21%, 6% and 1.2% at ρ=0.9 with 500, 2000 and 10⁴ jobs, but at 5000 jobs the bias (−0.14) is far below the run-to-run RMSE (2.4). Negative result: fixed deletion does not lower RMSE, and MSER-5 truncation leaves a larger bias (−0.77), covers 61% against 72% for no truncation, and passes a violating system 28% of the time against 18%. Stylised (Gaussian AR(1), M/M/1, simulated “real” system).

A figure from its own output

Paper, code and results

• README and method
• White paper
• Experiments and results
• Code
• Tests

More in Digital twins & sim-to-real

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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.