Which assumed input of the replicating-printer growth model does the doubling time depend on most?
research/selfrep-sensitivity
Which assumed input of the replicating-printer growth model moves its doubling time (Sobol indices, stylised, assumed ranges): budget and vitamin cost together carry ~90% of the variance when imports bind; when machine time binds, failure, print rate, budget and price are comparable.
What it found
Follow-up to selfrep-growth: variance-based (Sobol) sensitivity of the fluid-model doubling time to print rate, assembly time, vitamin cost, import budget and build-failure probability over assumed ranges. Import-limited (4/h): budget and vitamin cost carry about 0.45 and 0.43 of the variance of ln T, failure 0.11, print rate and assembly time none. Time-limited (64/h): budget, vitamin cost, failure and print rate are comparable (0.25–0.28). The fluid model overstates budget sensitivity at 64/h against the discrete-event model (elasticity −0.45 vs −0.02). Stylised, with assumed ranges and inputs.
A figure from its own output
Paper, code and results
More in Self-replicating manufacturing
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- How much does a smooth copy-then-sell policy beat a single switch for the replicating shop, certified without interpolation?An interpolation-free DP (the table equals its own policy's value to 1e-14): with no resale value and a saturating market a three-phase policy beats the best single switch by 4.7% (c = 1e4) to 7.1% (c = 1e3), while a resale value of 50 makes one switch optimal; a stylised fluid model, preliminary.
- How does a falling resale price for the finished fleet change when the shop stops copying?A resale price for the finished fleet that falls with market depth
m(stylised): with an unsaturated goods market the switch moves from 574 h (linear) to 549 h (m = 1e3) and a single switch matches the DP; with a saturating goods market the DP beats the best switch by up to 14%. - How much do the RepRap closure numbers depend on which parts a shop is judged able to make?How much the RepRap closure numbers depend on which parts a shop is judged able to make (stylised, assumed inputs): buying all optimistic lines cuts mass closure from 22% to 17%; making the motors in-house would add 22 points.
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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.