A simple ising model implementation (in C)

A simple enough implementation of the ising model in C. The parameters to the model, such as the size of the board, maximum number of sweeps to execute, and temperature of the system, is configured through the #define macros at the head of ising.c. Yeah, yeah, I'll change it someday.

The program outputs a series of .ppm frames that can be piped to a video encoder such as x264:

./ising | x264 --fps 60 -o video.mp4 /dev/stdin

Then you get a nice ol' video.