# Posts

### Dummy variables in R

Dummy variables are important but also cause much frustration in intro-stat courses. Below I will demonstrate the concept via a linear …

### caracas: Computer Algebra in R via SymPy

It is with great pleasure that we can announce the release of caracas version 1.0.1 to CRAN …

### Shiny apps with math exercises

It is often very useful to practise mathematics by automatically generated exercises. One approach is multiple choice quizzes (MCQ), …

### Ryacas version 1.1.0 publised in Journal of Open Source Software and released to CRAN

It is with great pleasure that I can announce that Ryacas version 1.1.0 has now been accepted into Journal of Open Source Software and …

### Variance in reproductive success (VRS) in forensic genetics lineage markers

Back in 2017, David Balding and I published the paper “How convincing is a matching Y-chromosome profile?”. One of the key parameters …

### Wolfe conditions for deciding step length in inexact line search: An example with the Rosenbrock function

In inexact line search (a numerical optimisation technique) the step length (or learning rate) must be decided. In connection to that …

### Ryacas version 1.0.0 released!

It is with great pleasure that I can announce that Ryacas version 1.0.0 is now released to CRAN …

### Approximating small probabilities using importance sampling

Update Oct 14, 2019: Michael Höhle caught a mistake and notified me on Twitter. Thanks! The problem is that I used \(\text{Unif}(-10, …

### How much pizza and how much frozen yogurt? ...with Gröbner bases

In a recent blog post I tried to get yacas to solve a system of polynomial equations. Unfortunately it could not do that, so I solved …

### Prediction intervals for Generalized Additive Models (GAMs)

Update on Aug 9, 2022: In the code chunk below, sd = summary(fit_gam)$scale) was changed to sd = sqrt(summary(fit_gam)$scale)): y_sim …