Machine Learning Fundamentals · free preview
Adam and Adaptive Learning Rates
Adam keeps two averages of the gradient, one for direction and one for magnitude, and divides the first by the square root of the second so each coordinate gets its own effective step size.
1. Two averages of the gradient
Two averages of the gradient
2. The initialization bias
The initialization bias
3. When the second moment misleads
When the second moment misleads
4. What the second moment does
Adam divides the momentum estimate by the square root of the second-moment estimate. Coordinate has seen consistently small gradients and coordinate consistently large ones. Which statement describes the relative step sizes, holding everything else fixed?
5. The bias correction at step 1
With and a first gradient , the momentum state is . The bias correction divides by , and the corrected estimate equals ____ in terms of .
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