Consider a complex number \(\gamma\) such that \(|\gamma| __ 1\) and the following matrix: \[ M = \begin{pmatrix} i & \gamma \\ \bar\gamma & -i \end{pmatrix}. \] ... [Read more...]

I’ve just submitted a new package to CRAN: jacobi. It allows to evaluate the Jacobi theta functions as well as some related functions. In particular, some Eisenstein series, that you will see below. ... [Read more...]

Here is a way to get a high-quality PNG image with R: save it as SVG first, then convert the SVG file to a PNG file, with the rsvg package. Let’s see. I construct a hyperbolic Delaunay trian... [Read more...]

It is easy to have a scrollbar for the sidebar of a Shiny app: one just has to use the CSS height: 90vh; overflow-y: auto;: library(shiny) library(shinyWidgets) ui [Read more...]

Remember my first post on the Hopf torus? I constructed it circle by circle. Below are some animations of this construction. I save the image each time a circle is added. The rgl package automatic... [Read more...]

Now the MeshesOperations package can construct the Minkowski sum of two polyhedra, thanks to the C++ library CGAL and the R package RcppCGAL. Let’s see an example: the Minkowski sum of Leonardo da... [Read more...]

I wanted to plot an algebraic isosurface with POV-Ray but the expression of the polynomial defining the isosurface was very long (the polynomial had degree 12). Moreover there was a square root in the coe... [Read more...]

I updated the gyro package (soon on CRAN). Here are the new features. Hyperbolic polyhedra in the Poincaré model The previous version of the package only dealt with hyperbolic ... [Read more...]

I published two posts here about my package RCGAL, the first one about surface reconstruction, and the second one about Boolean operations on 3D meshes. Now I decided to spli... [Read more...]

I refreshed my old package 'dir2json' (5 years old). It uses a Haskell DLL and can only work on Windows. You can install it from Github: remotes::install_github("stla/dir2json") ... [Read more...]

I really like the animated multibarchart of the JavaScript library NVD3. That?s why I did the ?Rnvd3? package. library(Rnvd3) dat [Read more...]

My package rAmCharts4 has a moderate success on Github (twenty stars). So I decided to present it here. [Read more...]

I?m still working on my package RCGAL, that I already present in a previous post. This previous post was about the reconstruction of surfaces. Now I implemented the Boolean operations on mes... [Read more...]

The R code below shows how to get a “Copy to clipboard” button in the plotly toolbar. library(plotly) set.seed(666L) asd [Read more...]

The E8 root polytope, its vertices and its edges The E8 root polytope, also known as the \(4_{21}\) polytope is a 8-dimensional polytope. The Cartesian coordinates of its vertices ar... [Read more...]

Some of my 3D animations start with a 4D object (such as a polytope) and I project it to the three-dimensional space with a stereographic projection. For example, the hyperbolic gircope. For this animatio... [Read more...]

This post is a demonstration of the cxhull and gyro packages. I will use these packages (and others) to draw an hyperbolic version of the stereographic projection of a convex 4D polytope, the gircope or ... [Read more...]

The problem Suppose you want to get the volume under a surface but you only have some points on this surface. For the illustration, I will take the surface defined by \(z = \exp\bigl(-(x^2 + y^2)\bi... [Read more...]

I am not a big fan of the built-in filters of DT. I prefer the ones below, made with the help of the JavaScript library select2. First, download the files sele... [Read more...]

My package gyro has been freshly released on CRAN. I implemented the ideas given in this blog post in this package. It has a short vignette. The gyrodemos function provides s... [Read more...]