It is well known that a rate-distortion-optimal source encoder's output generally doesn't match its source's distribution. This can make some analyses a pain in the neck. For example, say you want to investigate the relationship between a signal that appears in a source, and that signal's appearance in an encoding …

## Some Useful Multivariate Gaussian Information Quantities

Many information quantities for multivariate normal distributions have nice closed forms. Their essential parts usually reduce to logs of minor determinant quotients so they combine nicely. Here's a list of them. All of them are somewhere in Adaptive Wireless Communications by Bliss and Govindasamy.

## Notation

- [n]=\{1,\dots,n\}

## Combinatoral Iteration in Matlab

Often we need a to write a program that iterates over all combinations of k elements from some set (elements chosen without replacement). It isn't obvious how to efficiently traverse through all these sets, although if bitwise arithmetic is readily available one can use Gosper's Hack. This kind of …

## Some Interaction Information Examples

Interaction information between three random variables has a much less immediate interpretation compared to other information quantities. This makes it more tricky to work with. An i.i. term I(X;Y;Z) between X,\ Y and Z, could be either negative:

If …

## Porting PostmarketOS to the Motorola Photon Q

PostmarketOS has a goal to make old cell phones useful past their shelf life. Right now their efforts are towards getting Alpine Linux to run on as many phones as possible. The majority their codebase right now is a tool called

`pmbootstrap`

that automates parts of porting Alpine. Porting is …