3 ms·
State variables of dynamic systems can be arbitrary. The fact that two that were selected by an automatic process happened to correspond to the two angles is pr
by jovial_cavalier 4y ago
State variables of dynamic systems can be arbitrary. The fact that two that were selected by an automatic process happened to correspond to the two angles is probably more interesting than the other two being uncorrelated with the momenta.
- mike_hock 4y agoI guess it's because it's a serendipitous discovery by roboticists rather than an experiment explicitly set up to discover "alternative physics," but wouldn't it be much more efficient to feed the NN actual physical measurements rather than a video if discovering physical models was the goal? It's amazing that the AI found two variables that corresponded to actual physical phenomena just from video footage but it seems highly unlikely that it found an alternative description of physics given how far off the answer was. The NN could be modeling any kind of weird "fantasy" for how the visual signal it was being fed could be produced that might not even correspond to 3D space in a meaningful way.
- jovial_cavalier 4y agoThere should be four state variables for a double pendulum system - angle 1, angle 2, momentum 1, momentum 2. But they don't have to be neatly divided up like that. Angle 1 could be represented by some proportion of all four quantities. The individual variables can have no physical significance in of themselves whatsoever as long as there is a mechanism for turning them into the final answer.
- daveguy 4y agoIt's interesting that the angular explanatory variables are also those that are easily measured in a 2d still image. Whereas the angular velocity requires differential information and is not be immediately represented in each individual image.