- `Z = abs(X)`

Compute the magnitude of `X`.

The magnitude is defined as `%abs(Z) = sqrt(x^2 + y^2)%`.

For example:

> > `abs(3 + 4i)`

> > `%abs(3+4i)=5%`

See also: `arg`.

### References

- https://www.mathworks.com/help/matlab/ref/abs.html
- https://octave.sourceforge.io/octave/function/abs.html
- https://mathworld.wolfram.com/AbsoluteValue.html
- https://en.wikipedia.org/wiki/Absolute_value