graywolf is a fork of TimberWolf 6.3.5 TimberWolf was developed at Yale University, and was distributed as open source for a time until it was taken commercial. The last open-source version of TimberWolf does not perform detail routing, but is a professional-grade placement tool. In order to continue improving the open-source version, graywolf has been forked off from version 6.3.5 of TimberWolf. The main improvement in graywolf is that the build process is more streamlined and that it behaves as a normal linux tool - you can call it from anywhere and no environment variables must be set first.
