Maths for ML / Notation

\mathbb{R}

real numbers

Number systemsBeginner

Say it “R / the reals”

All numbers on the number line, including decimals and irrationals.

Example

x \in \mathbb{R}

x is a single real number (a float).

In code

float

Where you’ll see it in ML

Almost every weight and activation is a real number.

Don’t confuse it with

$\mathbb{R}^{n}, \mathbb{R}^{m\times n}$ real vector / matrix space ℝⁿ is the set of length-n real vectors; ℝ^{m×n} is the set of m-by-n real matrices. It tells you shape.

Related

Lessons that use it

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