Numerix.py behaves quite differently from what its doc string says. Here is a revised doc string that describes how it behaves at present, with => highlighting the differences:
"""numerix imports either Numeric or numarray based on various selectors.
0. If the value "--numarray" or "--Numeric" is specified on the
command line, then numerix imports the specified array package.
1. The value of numerix in ~/.matplotlibrc: either Numeric or numarray
=>2. The value of numerix in /usr/share/matplotlib/.matplotlibrc, as above.
(**I don't know what the Windows equivalent is.**)
=>3. The value of numerix in matplotlib/__init__.py, in the defaultParams
dictionary, which is presently "Numeric". Only if this is changed to None
will the search continue.
4. If the environment variable NUMERIX is defined as either "Numeric"
or as "numarray", then numerix will import from the specified array package.
5. If the file numerix or .numerix in the HOME directory of the current
user contains a single line specifying either "Numeric" or "numarray",
then the specified array package is imported.
6. If none of the above is done, the default array package is Numeric.
7. If the Numeric is selected and the import fails, numarray is tried.
To summarize: the commandline is examined first, the rc file seconds,
the environment third, the configuration file next, and the default
array package is Numeric. If everything else fails, numarray is tried.
=>In a standard matplotlib installation, however, only the first two
methods--command line and the user's rc file--of specifying the array
package will be effective for the unprivileged user.