Generate a random code!
How to use the code generator An introduction to random graph construction (primary source) 
This applet constructs an (N,K) code randomly based on the principles of stopping sets using an iterative algorithm presented in the source given above. It can construct codes of different distances and degrees. The code is represented both by its bipartite Tanner graph, which can be used in message passing algorithms for decoding and its paritycheck matrix.
