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Riemann

Riemann is an R package for learning with data on Riemannian manifolds. In statistics and machine learning, the term manifold appears in two realms; one is dimensionality reduction where we assume that low-dimensional data manifold is embedded in high-dimensional Euclidean space. The other is statistics on manifolds - data lie on some Riemannian manifolds that we are already well aware of. Riemann aims to achieve the latter. If you are interested in dimension reduction, please check another R package Rdimtools.

Installation

  • Option 1 : released version from CRAN.
install.packages("Riemann")
  • Option 2 : development version from GitHub.
if (!require("devtools")) {
  install.packages("devtools")
}
devtools::install_github("kisungyou/Riemann")

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Version

Install

install.packages('Riemann')

Monthly Downloads

621

Version

0.1.6

License

MIT + file LICENSE

Maintainer

Kisung You

Last Published

September 26th, 2025

Functions in Riemann (0.1.6)

ERP

Data : EEG Covariances for Event-Related Potentials
grassmann.optmacg

Estimation of Distribution Algorithm with MACG Distribution
gorilla

Data : Gorilla Skull
acg

Angular Central Gaussian Distribution
predict.m2skreg

Prediction for Manifold-to-Scalar Kernel Regression
label

S3 method for mixture model : predict labels
riem.distlp

Distance between Two Curves on Manifolds
orbital

Data : Normal Vectors to the Orbital Planes of the 9 Planets
hands

Data : Left Hands
passiflora

Data : Passiflora Leaves
riem.dtw

Dynamic Time Warping Distance
cities

Data : Populated Cities in the U.S.
riem.kmeans

K-Means Clustering
riem.interp

Geodesic Interpolation
riem.hclust

Hierarchical Agglomerative Clustering
riem.clrq

Competitive Learning Riemannian Quantization
grassmann.runif

Generate Uniform Samples on Grassmann Manifold
grassmann.utest

Test of Uniformity on Grassmann Manifold
riem.phate

PHATE
riem.kmeans18B

K-Means Clustering with Lightweight Coreset
riem.pga

Principal Geodesic Analysis
riem.mds

Multidimensional Scaling
moSL

Finite Mixture of Spherical Laplace Distributions
moSN

Finite Mixture of Spherical Normal Distributions
riem.pdist

Compute Pairwise Distances for Data
riem.pdist2

Compute Pairwise Distances for Two Sets of Data
riem.isomap

Isometric Feature Mapping
riem.interps

Geodesic Interpolation of Multiple Points
density

S3 method for mixture model : evaluate density
riem.rmml

Riemannian Manifold Metric Learning
riem.knn

Find K-Nearest Neighbors
riem.kpca

Kernel Principal Component Analysis
riem.wasserstein

Wasserstein Distance between Empirical Measures
riem.sammon

Sammon Mapping
rmvnorm

Generate Random Samples from Multivariate Normal Distribution
riem.median

Fréchet Median and Variation
riem.scSM

Spectral Clustering by Shi and Malik (2000)
riem.fanova

Fréchet Analysis of Variance
riem.nmshift

Nonlinear Mean Shift
loglkd

S3 method for mixture model : log-likelihood
spd.pdist

Pairwise Distance on SPD Manifold
riem.scUL

Spectral Clustering with Unnormalized Laplacian
spd.geometry

Supported Geometries on SPD Manifold
macg

Matrix Angular Central Gaussian Distribution
riem.kmeanspp

K-Means++ Clustering
wrap.stiefel

Prepare Data on (Compact) Stiefel Manifold
sphere.runif

Generate Uniform Samples on Sphere
sphere.utest

Test of Uniformity on Sphere
stiefel.utest

Test of Uniformity on Stiefel Manifold
wrap.spdk

Prepare Data on SPD Manifold of Fixed-Rank
wrap.correlation

Prepare Data on Correlation Manifold
stiefel.optSA

Simulated Annealing on Stiefel Manifold
wrap.sphere

Prepare Data on Sphere
riem.scNJW

Spectral Clustering by Ng, Jordan, and Weiss (2002)
sphere.convert

Convert between Cartesian Coordinates and Geographic Coordinates
spd.wassbary

Wasserstein Barycenter of SPD Matrices
riem.sc05Z

Spectral Clustering by Zelnik-Manor and Perona (2005)
wrap.landmark

Wrap Landmark Data on Shape Space
riem.kmedoids

K-Medoids Clustering
riem.m2skregCV

Manifold-to-Scalar Kernel Regression with K-Fold Cross Validation
riem.m2skreg

Manifold-to-Scalar Kernel Regression
riem.seb

Find the Smallest Enclosing Ball
riem.mean

Fréchet Mean and Variation
wrap.multinomial

Prepare Data on Multinomial Manifold
stiefel.runif

Generate Uniform Samples on Stiefel Manifold
wrap.grassmann

Prepare Data on Grassmann Manifold
riem.tsne

t-distributed Stochastic Neighbor Embedding
wrap.euclidean

Prepare Data on Euclidean Space
riem.test2wass

Two-Sample Test with Wasserstein Metric
wrap.rotation

Prepare Data on Rotation Group
splaplace

Spherical Laplace Distribution
riem.test2bg14

Two-Sample Test modified from Biswas and Ghosh (2014)
spnorm

Spherical Normal Distribution
wrap.spd

Prepare Data on Symmetric Positive-Definite (SPD) Manifold
riem.coreset18B

Build Lightweight Coreset