Posts

In a recent blog post I used something like this (for use in a call to optim()): obj_fun_expr <- expression((x^4 + 4 * x^2 * y^2 - …
Last updated on 3 min read R

Let \(\rho_{XY}\) be the correlation between the stochastic variables \(X\) and \(Y\) and similarly for \(\rho_{XZ}\) and …
Last updated on 6 min read Statistics, R, R-bloggers

It is important to test software. One approach is unit-testing, and for R packages this can e.g. be done using testthat. It is also …
Last updated on 3 min read R, R-bloggers

Update Aug 10, 2019: I wrote a new blog post about the same as below but using a simulation approach. Update Aug 27, 2019: Minor change …
Last updated on 5 min read Statistics, R, R-bloggers

Update Aug 27, 2019: I wrote a new blog post showing that Ryacas can now solve the system of equations directly without using optim(). …
Last updated on 13 min read R, R-bloggers

I am learning how to play piano. In that process, I needed charts with piano chords. I know it is good practise to construct the chords …
Last updated on 4 min read R, R-bloggers

Update Aug 27, 2019: Minor change in how equations are solved (from version 0.9.0.9122). We (Søren Højsgaard and I) are preparing a new …
Last updated on 5 min read R