Spherical Principal Curves
Calculating reconstruction error
Crossproduct of vectors
The number of distinct points.
Exponential map
Finding Extrinsic Mean
Generating circle on sphere
Finding Intrinsic Mean
Gaussian kernel function
Indicator kernel function
Quartic kernel function
Logarithm map
Local principal geodesics
Principal geodesic analysis
Principal circle on a sphere
Projecting the nearest point
Rotating point on a sphere
Rotating point on a sphere
principal curves by Hauberg on a sphere
Spherical principal curves
Transforming into Euclidean coordinate
Transforming into spherical coordinate
Fitting dimension reduction methods to data lying on two-dimensional sphere. This package provides principal geodesic analysis, principal circle, principal curves proposed by Hauberg, and spherical principal curves. Moreover, it offers the method of locally defined principal geodesics which is underway. The detailed procedures are described in Lee, J., Kim, J.-H. and Oh, H.-S. (2021) <doi:10.1109/TPAMI.2020.3025327>. Also see Kim, J.-H., Lee, J. and Oh, H.-S. (2020) <arXiv:2003.02578>.