# Length

Return the length of the input vector, with three possible distance definitions:

#### Euclidian

The "ordinary" length of the vector:  $$\sqrt{x^2+y^2+z^2}$$

Euclidian distance squared, which is cheaper to compute:  $$x^2+y^2+z^2$$
Measures distance following only axis-aligned directions, which is even cheaper to compute:  $$\left|x\right|+\left|y\right|+\left|z\right|$$