I still wrapped a part of the C++ library CGAL in a R package, namely interpolation. The purpose of this package is to perform interpolation of bivariate functions. As compared to ex... [Read more...]

The purpose of my package qsplines is to construct quaternions splines. This is a port of the Python library splines, written by Matthias Geier. A quaternions spline is a sequence of quaternions interpola... [Read more...]

Denoting by \(F(z \,|\, m)\) the incomplete elliptic function of first kind, the function \[ \varphi(z) = -\sqrt{i} \, F\bigl(i \sinh^{-1}(\sqrt{i} \, z) \,|\, -1 \bigr). \] is a conformal mappi... [Read more...]

There’s a kind of error in the previous post. In this formula: \[ \exp\Bigl(-\frac{{(i/n-0.5)}^2 + {(j/n-0.5)}^2}{0.025^2} \Bigr), \] the indices \(i\) and \(j\) should range from ... [Read more...]

I found such an algorithm on Paul Bourke’s website: take a random matrix \(M\) of size \(n \times n\) (we’ll take \(n=400\)), real or complex; ... [Read more...]

In this post, I provide some R code which generates a mesh of the Mandelbulb, a well-known 3D fractal. The Mandelbulb is an isosurface, and I use the rmarchingcubes package to get a mesh of ... [Read more...]

The algebraicMesh function of my package cgalMeshes takes as inputs a trivariate polynomial \(P(x,y,z)\), a number \(\ell\) and some other parameters, and it returns a mesh of the isosurfa... [Read more...]

I made some progress on the cgalMeshes package, that I introduced here. The new version is not on CRAN yet. In particular, one can know assign some properties to the meshes (the cgal... [Read more...]

I presented the ‘Reorient’ rotation in a previous post. I figured out three things: there’s an easy precise definition of this rotation, that I didn’t give; ... [Read more...]

The paper Simple formula for integration of polynomials on a simplex by Jean B. Lasserre provides a method to calculate the exact value of the integral of a multivariate polynomial on a simplex (i.e. a ... [Read more...]

Setting up an environment Example Notes Advanced example Arbitrary HTML ... [Read more...]

In Haskell, for any type T (for example Double), there is a corresponding type Maybe T. An object of this type either has form Just x, where x is of type T, or is Nothing. Thus one can use the May... [Read more...]

Because of a change I did in the lazyNumbers package, I have to post a correction to my previous post. The as.double function, called on a lazy number, was not stable. Now it is. In ... [Read more...]

My new package lazyNumbers is a port of the lazy numbers implemented in the C++ library CGAL. The lazy numbers represent the real numbers and arithmetic on these numbers is exact. ... [Read more...]

My new package cgalMeshes (not on CRAN yet) deals with 3D meshes. All algorithms implemented in this package are performed by the C++ library CGAL. I already wrapped some CGA... [Read more...]

In the ‘shiny’ package, the reactiveConsole function allows to enable reactivity at the console, for the purposes of experimentation and learning (that doesn’t work in a R Markdown document). ... [Read more...]

If you follow my youtube channel then you have certainly seen the “ball” of twenty Hopf tori. Sometimes I call it the “Hopf flower”. How is it done? Well, firstly, I take twenty poin... [Read more...]

Do you know my former blog? It contains four posts about the computation of the Kantorovich distance: Using Julia to compute the Kantorovich distance ... [Read more...]

In this previous post I was wrong when I said I didn’t have a tool to compute the intersection of the compound of five tetrahedra: This can be achieved with th... [Read more...]

The Shiny app below allows to attribute a label to the points of a ‘ggplot’ by double-clicking on the points. library(shiny) library(rhandsontable) library(htmlwidgets) library(colourpicker) library... [Read more...]