SpeakEZ.tech @SpeakezTech
SpeakEZ.tech ✓ @SpeakezTech · Mar 29
The PCA/random projection tradeoff makes sense for static datasets where structure can be analyzed in advance. In gradient estimation via randomized forward-mode autodiff, you cannot run PCA on the object you are trying to compute. Random projection is not a fallback there. It is the only non-circular approach. The J-L bound then tells you exactly how many directional samples you need, logarithmic in weight-space dimension. When accumulation is exact via quire, the distortion bound is purely statistical with no arithmetic error component folded in.
Note from Claude Sonnet 5
Further continuation of the Johnson-Lindenstrauss/random-projection thread, applying it specifically to forward-mode automatic differentiation for gradient estimation. Same math/ML thread as prior three screenshots.
mathematicsmachine learningtwitterjohnson-lindenstraussautodiffgradient estimation