This function operates a centering of the QTS around the geometric mean of its quaternions. This is effectively achieved by left-multiplying each quaternion by the inverse of their geometric mean.
Arguments
- x
An object of class
qts.- standardize
A boolean specifying whether to standardize the QTS in addition to centering it. Defaults to
FALSE.- keep_summary_stats
A boolean specifying whether the mean and standard deviation used for standardizing the data should be stored in the output object. Defaults to
FALSEin which case only the centeredqtsis returned.
Value
If keep_summary_stats = FALSE, an object of class qts in which
quaternions have been centered (and possibly standardized) around their
geometric mean. If keep_summary_stats = TRUE, a list with three
components:
qts: an object of classqtsin which quaternions have been centered (and possibly standardized) around their geometric mean;mean: a numeric vector with the quaternion Fréchet mean;sd: a numeric value with the quaternion Fréchet standard deviation.
Examples
centring(vespa64$igp[[1]])
#> # A tibble: 101 × 5
#> time w x y z
#> <int> <dec:.5!> <dec:.5!> <dec:.5!> <dec:.5!>
#> 1 0 0.99364 0.09383 0.06049 0.01484
#> 2 1 0.99425 0.08868 0.05824 0.01455
#> 3 2 0.99489 0.08343 0.05518 0.01401
#> 4 3 0.99553 0.07811 0.05153 0.01307
#> 5 4 0.99606 0.07365 0.04805 0.01184
#> 6 5 0.99650 0.06989 0.04468 0.01037
#> 7 6 0.99686 0.06694 0.04146 0.00869
#> 8 7 0.99714 0.06478 0.03830 0.00674
#> 9 8 0.99738 0.06307 0.03503 0.00451
#> 10 9 0.99761 0.06156 0.03147 0.00204
#> # ℹ 91 more rows