4 ms·
This is absolutely not the case for most physical simulations where the significant digits are more important than fixed decimal accuracy.
by gyrovagueGeist 3y ago
This is absolutely not the case for most physical simulations where the significant digits are more important than fixed decimal accuracy.
- aidenn0 3y agoConsider a simple newtonian physics simulation. What you say is probably true for both force and acceleration. It may be true for velocity, but is almost certainly not true for position. Consider an object with a very small velocity traveling away from the origin with no forces acting upon it. With floating-point arithmetic, it will eventually stop at some distance away from the origin. In general objects with small velocity will only move if they are close to the origin.
- gyrovagueGeist 3y agoSure, but most PIC methods are centered at their element or local domain. (You can likely even do the same with ewald/nbody). I definitely agree with you though if you need high accuracy on position when everything is on the same huge grid. A simulation that computes bulk properties by simulating particles directly is very rare. At least for me. Observable like temperature, electric/magnetic field strength, stress, velocity, etc are much more common outputs. These often all vary over many order of magnitude across a domain. Working with continuum mechanics, performing large inverted solves on matrices in fixed precision, or heck, even an FFT sounds terrifying to guard against overflow.