penacho doc is a comprehensive PDF report (>100 pages) written in LaTeX. It includes physic modeling, resolution algorithm, users' manual, and programmers' manual.
LaTeX mathematical equations and symbols match exactly those on the source code. A table references every equation label (e.g. eq:Wx) with its equation number and page.
This doc is written in Spanish... but Math is the universal language. penacho user interface and code are in English.