Iteration count of the improved variant of Stern’s algorithm for binary linear codes by Daniel J.  Bernstein, Tanja Lange, and myself published at PQCrypto 2008.

Compute the iteration counts for our attack on the McEliece cryptosystem using the type-3 Markov-chain analysis.

https://github.com/christianepeters/isdf2

The implementation is written in C and uses the MPFI library. Note that you might need to increase the level of precision if you consider codes of length greater than 1024. Change the line

int prec = 150;

to something more convenient.

See also the post on ISDFq.