Maths for ML / Notation

ϵ\epsilon

epsilon

Greek letters and conventionsBeginner

Say it “epsilon”

A tiny positive number — or, in models, a noise term.

Example

xσ2+ϵ\frac{x}{\sqrt{\sigma^2 + \epsilon}}

Avoids divide-by-zero in normalization.

In code

eps = 1e-8
torch.nn.LayerNorm(d, eps=1e-5)

Where you’ll see it in ML

Numerical stability in Adam/LayerNorm; ε-greedy in RL; noise in diffusion.

Don’t confuse it with

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