HEFT : Heterogeneous Earliest Finish Time, a static scheduling algorithm.
http://en.wikipedia.org/wiki/Heterogeneous_Earliest_Finish_Time
The random DAGs are created by TGFF. For details, see the following. http://ziyang.eecs.umich.edu/~dickrp/tgff/
section { 1. Tasks 2. Edges }
section { 1. Matrix of computational overhead }