param: Parameters are a kind of class attribute allowing special behavior,
including dynamically generated parameter values, documentation
strings, constant and read-only parameters, and type or range checking
at assignment time.
param.external: External code required for param/tkinter interface.
param.parameterized: Generic support for objects with full-featured Parameters and
messaging.
topo.learningfn.optimized: Learning functions (see basic.py) and projection-level learning
functions (see projfn.py) written in C to optimize performance.
topo.misc.fixedpoint: FixedPoint objects support decimal arithmetic with a fixed number of
digits (called the object's precision) after the decimal point.
topo.misc.gendocs: Topographica-specific changes to the standard pydoc command.