Talk:Molecular dynamics

Ewald isn't what drops the time scaling from O(N^2)

This isn't quite correct as stated in the article. Ewald, PPM, etc. used in conjunction with neighbor cutoffs is what does this. It is possible to pick a cutoff so big that the scaling of the system is still effectively O(N^2) even with long range corrections. Spherical cutoffs drop the simulation down to O(N * k) where k is the typical number of particle within the cutoff because you are still computing an average of k interactions O(N) times for each particle in the system. Since the cutoff is fixed this usually is approximately O(N) since k typically doesn't change much in most simulations even as the system is scaled. That is unless you're doing a system which undergoes a radical change. For example a phase change from a sparse phase to a dense one.

Mesh methods take this up to a O(k N log(N)), However if the cutoff is sufficiently large then k => N as r_cut => L_box/2. In practice no one picks a r_cut where k can approach N, but it's just there to illustrate that the Ewald isn't the source of the scaling reduction.

Ewald is there to account for electrostatic and other interactions greater than the box length that exist in bulk system. You still need this even if you choose to use larger cutoffs. Which BTW, Ewald is actually still a O(N^2) algorithm. It's Particle Mesh approaches which get down to O(N log N) — Preceding unsigned comment added by 50.52.82.3 (talk) 22:14, 17 October 2025 (UTC)

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Should we fix "Examples of applications" section or leave it?

Hi, I am of the opinion that the Examples of applications section should give a more general overview of applications rather than focusing on specifics like it seems to currently. It very heavily references primary literature, what do you think? EvilxFish (talk) 14:38, 25 April 2018 (UTC)

Milestones can still be mentioned but general overview would seem better Galobtter (pingó mió) 17:25, 29 April 2018 (UTC)

Term Atomistics

The term "Atomistics" redirects here, but the article makes no use of the term. Are the terms "Molecular dynamics" and "Atomistics" synonymous, or should Atomistics be a topic within Molecular dynamics? I don't have enough knowledge about the field to know the best way to resolve this. Thank you. MissionInn.Jim (talk) 20:45, 23 November 2019 (UTC)

History of MD

What's about it? Жабыш (talk) 05:47, 3 December 2019 (UTC)