The Walrus Binary Entropy Coder

Arithmetic coders do their job so well that they're nearly synonymous with it. The Walrus is an example of a coder that does the same job very nearly as well, using a different kind of mapping between symbols and bits.

This essay is literate Python (block comments interspersed with code) that clarifies the job requirements and pinpoints where coders can differ and still meet the requirements. The code includes both coders, and correctness tests, and there's a separate notebook that compares the two coders' efficiency.

The file is renamed .txt here because of an issue with my web server's configuration.

The section about efficiency is below in images-inlined HTML as well as the original ipynb form.

Walrus with bucket	Eggman with chicken and eggs	Arithmetic coders slice pies; the Walrus subdivides brownies.

This static page was made with a php script. Last change January 22, 2021.
--Steve Witham Up to my temporary home page.

`Makefile (1K)`
`Walrus_thumb2.png (10K)`
`eggmanstatue.jpg (22K)`
`i_has_a_bucket.jpg (116K)`
`i_has_a_bucket_crop.jpg (58K)`
`index.html (2K)`
`makeindex.php.txt (4K)`
`pieversuscake.png (28K)`
`test1_12.out (9K)`	Data used by the Jupyter notebook
`walrus_effish_graphs.html (852K)`	[N] Notebook as HTML with efficiency graphs
`walrus_effish_graphs.ipynb (260K)`	[N] (Jupyter notebook source)
`walrus_piece_py.txt (45K)`	The paper as literate code