Using Vectorization to Measure Velocity

Continuing my work on the applications of A.I. to physics, in this article, I’m going to present very simple software that can take a large number of observations of an object, that has a macroscopic rectilinear motion, and calculate its velocity.

The reason this software is interesting, is because the motions of the objects are random, but nonetheless generate a macroscopically rectilinear motion. This is how real world objects actually behave, in that the parts of a projectile don’t move in the same direction at the same time, but instead have variability that simply isn’t perceptible to human beings, but might nonetheless get picked up by a sensor, making the problem of measuring velocity non-trivial, when given a lot of data.

Though you don’t need to read it to appreciate the software I’ll present in this article, all of this is based upon my model of motion, which I presented in my main paper on physics, “A Computational Model of Time-Dilation” –

I’m simply memorializing the model using code, which will eventually allow for a complete model of physics, including the correct equations of time-dilation, that can be easily analyzed using my entire library of A.I. software.

My ultimate goal is to allow for the autonomous discovery of useful models of physical systems, leaving physicists free to do the higher work of discovering theoretical connections between observables, and then allowing machines to uncover approximations of their relationships, which should in turn assist physicists in their discovery of the correct, exact, mathematical relationships. This software will also be useful for the cases where the correct relationship is impossible to discover, due to intractability, or because it simply doesn’t exist in the first instance, which is a real possibility, if reality is non-computable. There’s also, obviously, the commercial case, where you don’t need the correct equation, and a model that works is all you really need.

Screen Shot 2020-08-15 at 12.05.00 PM

A statistical sphere moving in Euclidean space over 16 frames of observation.

The example in this case consists of a statistical sphere, that has 1,000 independently moving points, that change position over a series of 16 frames. The velocities of the points are independent, but selected in a manner that ensures that the relative positions of the points remain approximately constant on average over time. For an explanation of the mathematics underlying the model, see Section 3.3 of the paper linked to above, but you can plainly see combinatorial relationships unfolding in the paths of the individual points, with the outcomes more dispersed in the center of each path, which I’ll explore in a follow up article, clustering the paths of the particles, and generating state graphs.

The method itself is incredibly simple:

The algorithm approximates the origin of the shape in each frame, by taking the average over each of the x, y, and z coordinates, separately, for each frame, assuming the overall shape is a sphere, which it obviously isn’t, since there’s some dispersion. However, it doesn’t matter, because the dispersion is roughly symmetrical, producing a meaningful point from which we can measure displacement.

The rate of displacement in this approximated origin is then calculated for each frame, and compared to the true, average displacement over the entire set of points for each frame. If there are N frames, then this process will calculate the true average velocity for each frame, expressed as an N \times 3 matrix, and compare that to the approximated average velocity for each frame, also expressed as an N \times 3 matrix (note that the x, y, and z velocities are independent).

Approximating the average velocity takes about 2 seconds running on an iMac, and the  average error is O(10^{-14}).

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