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squat (development version)

squat 0.3.0

CRAN release: 2024-01-10

New features

  • Added S3 specialization of the stats::predict() function for prcomp_qts objects.
  • Added function qts2aats() which allows to switch from quaternion to axis-angle representation of rotations.
  • Added usual operations +, -, * and inverse_qts() for quaternion time series using the Eigen library.

Small improvements

  • Make sure quaternion geodesic mean is not flipped.
  • Fix issues in PCA:
    • avoid numerical overflows due to bad choice of k in gam();
    • improved documentation;
    • Use same number of basis functions in uni- and multivariate decompositions.
  • Updated GHA scripts and README.
  • Fix bug related to Rcpp following RcppCore/Rcpp#1287.

squat 0.2.1

CRAN release: 2023-07-09

  • Add use_fence robustification option;
  • Adapt to changes in fdacluster;
  • Properly compute tangent spaces along mean QTS;
  • Update News section of website.

squat 0.2.0

CRAN release: 2023-06-04

Major features:

  • Added hierarichal clustering;
  • Added DBSCAN clustering;
  • Added distance matrix computation.

Minor improvements:

  • Adapted code to match new API in fdacluster package.

squat 0.1.0

CRAN release: 2022-12-22

Major statistical features

  • A first API proposal with a class qts and a class qts_sample for which a number of methods are properly implemented.
  • Available statistical methods for QTS samples:
    • random generation according to the Gaussian functional model via rnorm_qts(),
    • scale(),
    • mean(),
    • median(),
    • distance matrix computation via distDTW() (i.e. for now we use the dynamic time warping),
    • tangent principal component analysis via prcomp(),
    • k-means with optional alignment via kmeans().
  • Added multiple ways of displaying samples of QTS.
  • Added two example datasets.


  • Make all functions applicable to a single QTS also applicable to QTS samples, with appropriate class for the output.
  • Enable as_qts_sample() to generate a QTS sample of size 1 from a single QTS as input argument.
  • Rename change_points argument to the plot.qts() function to better reflect its flexibility.
  • Added subset operator for QTS sample objects.
  • Added append S3 method for QTS sample objects.
  • Added hemispherize() function to remove any discontinuities in QTS due to quaternion flips.
  • Any parallelization computation is now handled using the futureverse principles and, in particular, implemented through the use of the furrr package.

squat 0.0.1

CRAN release: 2022-09-27

  • Added a file to track changes to the package.
  • Initial version.