I’ve updated the directions as to how to build 64-bit R for Windows linking to OpenBLAS, as the entire R build process for Windows will change for R version 3.2 and subsequent. I’ve turned it into a static page, instead of a post, in case the build process changes again. While the title has 3.2 in it, the URL doesn’t, so it should be future-proof. Then again, that’s number 47 on the list of 996 famous last words! As always, I’m interested in hearing if anyone successfully builds it and how much of a difference it makes. ∞
Flavors of risk: process, parameter, model, and unknown
I’ve recently been asked a number of times as to the differences between various sources of risks one is exposed to when creating a model, in specific, for the difference between parameter and model risk. I’ve used the following allegory a number of times to explain how I see the differences between process, parameter, model, Read the full article…
Big Data, Correlations, and the Hales-Jewett Theorem
“Big Data” has become one of the most heralded tools, or at least buzzwords, of this decade. The use of “big data” is trumpeted by many studies in almost all disciplines, and, too an extent, understandably so. Hand-in-hand with the geometric progression of computing power has been the development of algorithms that can parse huge Read the full article…
An OpenBLAS-based Rblas for Windows 64: Step-by-step
As a result of my previous post, I’ve had a number of requests to describe how I compiled the BLAS, so I’ll do so below. Of course, the necessary caveats, I am not a programmer nor do I play one on the radio so I probably cannot debug any issue anyone may have. Use the Read the full article…
An OpenBLAS-based Rblas for Windows 64
One of the more important pieces of software that powers R is its BLAS, which stands for Basic Linear Algebra Subprograms. This is the suite of programs which, as its name implies, performs basic linear algebra routines such as vector copying, scaling and dot products; linear combinations; and matrix multiplication. It is the engine on Read the full article…
Correcting a pseudo-correlation matrix to be positive semidefinite
In a recent LinkedIn conversation, the topic of correlation between multiple financial indices was raised. While the actual details are not relevant, the discussion reminded me of one of the concerns I have whenever multivariate correlation is used—how to populate the correlation matrix. First, some background. Unfortunately, most financial random variables are not normally distributed—they Read the full article…
Strange Attractors, Blogs, and Chaoscope
I admit it, I succumbed. I finally decided to bite the bullet and start a real blog. Of course, a real blog needs a name. After a period of brainstorming, I decided to name the blog Strange Attractors. What is a strange attractor? An attractor is a mathematical concept which refers to the limits to Read the full article…