In this post, I talk about loops in R, why they can be slow and when it is okay to use them. Don’t grow objects Let us generate a matrix of uniform values (max changing for every column). gen_grow

In this post, I talk about performance through an efficient algorithm I developed for finding closest points on a map. This algorithm uses both concepts from mathematics and algorithmics. Problem to solve This problem comes from a recent question on StackOverflow. I have two matrices, one is 200K rows long, the other is 20K. For each row (which is...

Last weekend, I discovered the pixel art. The goal is to reproduce a pixelated drawing. Anyone can do this without any drawing skills because you just have to reproduce the pixels one by one (on a squared paper). Kids and big kids can quickly become addicted to this. Example For this pixelated ironman, you need only 3 colors (black,...

In this post, I will analyze the results of the “épreuves classantes nationales (ECN)”, which is a competitive examination at the end of the 6th year of medical school in France. First ones get to choose first where they want to continue their medical training. A very clean dataset The data is in a PDF there. I’m not an expert in...

In this post, I will talk about parallelism in R. This post will likely be biased towards the solutions I use. For example, I never use mcapply nor clusterApply. I prefer to always use foreach. In this post, we will focus on how to parallelize R code on your computer. I will use mainly silly examples, just to show...

Hello everyone, I’m 6103040 aka F. Privé. In this post, I will give some insights about answering questions on Stack Overflow (SO) for a month. One of the reason I’ve began frenetically answering questions on Stack Overflow was to procrastinate while finishing a scientific manuscript. My activity on Stack Overflow We’ll use David Robinson’s package stackr to get data from Stack...

In this post, I will talk about my package bigstatsr, which I’ve just presented in a lightning talk of 5 minutes at useR!2017. You can listen to me in action there. I should have chosen a longer talk to explain more about this package, maybe next time. I will use this post to give you a more detailed version...

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