IWCSEC: Inverse Wulff Construction Surface Energy Calculation

=== A brief introduction to the library

IWCSEC is a library for calculating surface energies that corresponds to Wulff shapes.
Most programs that implement Wulff construction require surface energies as their
input parameters. For most cases, surface energies are unknown: they are difficult to
measure experimentally, and difficult to calculate computationally. Particle shapes
are much easier to be observed and quantified (to obtain edge lengths or surface 
areas). The IWCSEC library uses experimentally observed particle shapes as inputs and 
calculates surface energies. The surface energies are useful parameters for materials
models that involve surfaces.

=== Installation and usage
Most of the functions are written in Python; some speed-critical functions are
implemented in C. The C code by compilation generates a Python-callable extension
module. 

The library contains a collection of functions that can be called in other Python 
programs.

Alternatively, we have written a demonstration program that is to be used
interactively.

=== Installation
The library includes an extention module writen in the C programming language.
You will first use the following command to compile geometry.c into cgeometry.so:

    python setup.py build
    
The compiled module is in ./build/lib.???/ directory. 
You will need to copy it to the current directry, such that it can be imported properly.