Maths for ML / Notation

π\pi

pi

Greek letters and conventionsBeginner

Say it “pi”

About 3.14159 — the circle constant. In RL, π is a policy instead.

Example

π(a∣s)\pi(a \mid s)

An RL policy: probability of action a in state s.

In code

np.pi
torch.pi

Where you’ll see it in ML

Gaussian formulas contain π; RL uses π for policies.

Don’t confuse it with

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