I've finally hit the point where getting a program running is not enough. I have a functional Gaussian process and need to speed it up. Most of the time is used up by a conjugate gradient descent with ...

Consider a linear model Y = Xβ + z, where X = Xn,p and z ~ N (0, In). The vector β is unknown but is sparse in the sense that most of its coordinates are 0. The main interest is to separate its ...

Coxeter theory investigates groups generated by reflections and the geometric structures arising from their actions, such as root systems and Dynkin diagrams. This body of work underpins vast areas of ...