need an example of Python numarray to C++ and back again, Boost / SWIG?

[PL]

I want to pass a 2D array from Python to C++, manipulate it in C++ (for
example, add 1 to each element) and pass it back to Python.

With these building blocks I will be able to figure out all the rest of
what I need to do for my project.  I am very familiar with Python, but
less so with C++ and Boost or SWIG.

Does anyone have an example with all steps that I can follow?  More
specifically I am looking for the C++ code, ".i" file for SWIG and/or
the analagous setup files that Boost would need to do this.

Thanks in advance for any help you can provide,