# Articles by Stéphane Laurent

### Boolean operations on meshes with R(CGAL)

May 13, 2022 |

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...]

### Copy ‘plotly’ image to the clipboard

March 15, 2022 |

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

March 13, 2022 |

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...]

### The modified stereographic projection

February 28, 2022 |

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...]

### Hyperbolic gircope – using ‘cxhull’ and ‘gyro’

February 27, 2022 |

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...]

### Volume under surface from points

February 25, 2022 |

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...]

### Nice DT filters

February 10, 2022 |

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...]

### Gyrotriangle (aka hyperbolic triangle) with moving colors

February 4, 2022 |

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...]

February 2, 2022 |

In this blog post I introduce three small RStudio addins I did. ‘bracketify’ I prefer subsetting with the double brackets than with the dollar in R, because this is more readable in RS... [Read more...]

### Hopf torus with dynamic colors

January 28, 2022 |

In a recent post I explained how to decorate a surface with moving colors with the Python library PyVista. Here I expose this method for the R package rgl. I will take a Hopf... [Read more...]

### ‘gifski’ as a bash command using R

January 27, 2022 |

The gifski command-line utility is a great tool to make a GIF animation from a series of png files. At my work I’m using a laptop with Windows 10 and I don’t have admin rights. I don’t know how to install... [Read more...]

### Funny 3D Voronoï diagrams

January 18, 2022 |

Four years ago I wrapped the C library Qhull in a Haskell package. Thanks to Qhull, this package can do some convex hulls and some Delaunay tessellations. The Qhull library also allows to do some ... [Read more...]

### Surface reconstruction with R(CGAL)

January 14, 2022 |

Eric Dunipace recently released a new package on CRAN: RcppCGAL. It allows to link to the C++ library CGAL in Rcpp. The CGAL library provides an extensive set of algorithms for computational geome... [Read more...]

### Clipping an isosurface to a ball, and more

January 13, 2022 |

We will firstly show how to clip an isosurface to a ball with R, and then, more generally, how to clip a surface to an arbitrary region. In the last part we show how to achieve the same with Python. ... [Read more...]

### Bookmarking a Shiny app without Shiny bookmarking

December 8, 2020 |

I do not well remember, but it seems to me I faced some difficulties when I tried to use Shiny bookmarking to save and restore the state of a Shiny app. These difficulties arose when there were some rende... [Read more...]

### Generalized fiducial inference on quantiles

November 26, 2020 |

My new package ‘gfiExtremes’ is on CRAN now. So it is time to present it. This package allows to get confidence intervals about the quantiles of any reasonable distribution (although... [Read more...]

### Why I like generalized fiducial inference

November 7, 2020 |

Throughout this article, one considers the balanced one-way ANOVA model with a random factor (group). The between standard deviation and the within standard deviation are denoted by \(\sigma_{\mathrm{b}}\... [Read more...]

October 21, 2020 |

Updated title: Haskell is fast, but Julia is faster (see updates at the end). My R package ‘HypergeoMat’ provides a Rcpp implementation of Koev & Edelman’s algorithm for the eval... [Read more...]

### The ‘kde1d’ package

October 14, 2020 |

It seems to me that the kde1d package (One-Dimensional Kernel Density Estimation) is not very known. I’ve never heard of it on Stack Overflow, except in an answer of mine. However this is a ... [Read more...]

### My RGL artworks

October 7, 2020 |

These are some of my artworks realized with the R package rgl. Source code is available in my gists. ... [Read more...]
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