Tilings is a library for working with gridded permutations and tilings.
Permuta is a Python library for working with perms (short for permutations), patterns, and mesh patterns.
comb_spec_searcherpackage contains code for combinatorial exploration.
The file preim.sage contains algorithms developed by myself and Hjalti Magnusson for computing the preimage of any pattern class under two sorting operators: 1) A stack of depth d (you can put d equal to infinity); and 2) A queue. These are implemented in the computer algebra system Sage. What follow are instructions for using the algorithm. Please contact me via email if you find any bugs, want any clarifications or to suggest new features.