A collection of functions that implements the QTS class. It currently
provides the `as_qts()`

function for QTS coercion of `tibble::tibble`

s
and the `is_qts()`

function for checking if an object is a QTS.

## Usage

```
as_qts(x)
is_qts(x)
# S3 method for qts
format(x, digits = 5, ...)
```

## Arguments

- x
A

`tibble::tibble`

with columns`time`

,`w`

,`x`

,`y`

and`z`

.- digits
An integer value specifying the number of digits to keep for printing. Defaults to

`5L`

.- ...
Further arguments passed to or from other methods.

## Details

A quaternion time series (QTS) is stored as a `tibble::tibble`

with 5
columns:

`time`

: A first column specifying the time points at which quaternions were collected;`w`

: A second column specifying the first coordinate of the collected quaternions;`x`

: A third column specifying the second coordinate of the collected quaternions;`y`

: A fourth column specifying the third coordinate of the collected quaternions;`z`

: A fifth column specifying the fourth coordinate of the collected quaternions.