Backpropagation, while effective for gradient computation, falls short in addressing memory consumption, limiting scalability. This work explores forward-mode gradient computation as an alternative in invertible networks, showing its potential to reduce the memory footprint without substantial drawbacks. We introduce a novel technique based on a vector-inverse-Jacobian product that accelerates the computation of forward gradients while retaining the advantages of memory reduction and preserving the fidelity of true gradients. Our method, Moonwalk, has a time complexity linear in the depth of the network, unlike the quadratic time complexity of na\"ive forward, and empirically reduces computation time by several orders of magnitude without allocating more memory. We further accelerate Moonwalk by combining it with reverse-mode differentiation to achieve time complexity comparable with backpropagation while maintaining a much smaller memory footprint. Finally, we showcase the robustness of our method across several architecture choices. Moonwalk is the first forward-based method to compute true gradients in invertible networks in computation time comparable to backpropagation and using significantly less memory.

Chinese tech firm Xiaomi first developed its CyberDog two years ago to compete with rival company Boston Dynamics' Spot. Now it is unveiling an enhanced model, called CyberDog 2, which is even more intelligent and lifelike. Most importantly, it now much more closely resembles a dog than just a robotic creature with legs. That's because it has adopted a number of features resembling a Doberman, including adorable ears. New model: They say every dog has its day -- and that's true for the robotic pooch that has been superseded by this moonwalking, ballet dancing upgrade The four-legged robot is also much smaller and lighter than its predecessor, weighing just 19 lbs (8.9kg) compared to the CyberDog's 31 lbs (14kg).

Boston Dynamics continues to crank out viral-worthy videos of its robots busting strange and unexpected moves. The robotics company formerly owned by Google released on Tuesday a new video of its dog-like SpotMini robot dancing to a cover of Mark Ronson's "Uptown Funk." It even pulls off the robot-dog equivalent to a moonwalk. Previously SpotMini has gone viral for opening doors for its robot comrades. Boston Dynamics released no information to accompany the video, so it's entirely possible that Spotmini has been pre-programmed to dance.