As one learns at high school, the continuous derivative is the limit of the discrete version as the displacement h is sent to zero. If our computers could afford infinite precision, this statement would be equally good in practice as it is in continuum mathematics. But no computer can afford infinite precision, in fact, the standard double-precision IEEE representation of floating numbers offers an accuracy around the 16th digit, meaning that numbers below 10β16 are basically treated as pure noise. This means that upon sending the displacement h below machine precision, the discrete derivatives start to diverge from the continuum value as roundoff errors then dominate the discretization errors.
Yes, differentiating data has a noise problem. This is where gradient followers sometimes get stuck. A low pass filter can help by smoothing the data so the derivatives are less noisy. But is that relevant to LLMs? A big insight in machine learning optimization was that, in a high dimensional space, there's usually some dimension with a significant signal, which gets you out of local minima. Most machine learning is in high dimensional spaces but with low resolution data points.
βOn a loose but telling note, this is still three decades short of the number of neural connections in the human brain, 1015, and yet they consume some one hundred million times more power (GWatts as compared to the very modest 20 Watts required by our brains).β
No human brain could have time to read all the materials of a modern LLM training run even if they lived and read eight hours a day since humans first appeared over 300,000 years ago. More to the point, inference of an LLM is way more energy efficient than human inference (see the energy costs of a B200 decoding a 671B parameter model and estimate the energy needed to write the equivalent of a human book worth of information as part of a larger batch). The main reason for the large energy costs of inference is that we are serving hundreds of millions of people with the same model. No humans have this type of scaling capability.
I wonder if the authors are aware of The Bitter Lesson