Towards efficient large scale epidemiological simulations in EpiGraph Gonzalo Mart´ ın a,* , David E. Singh a , Maria-Cristina Marinescu b , Jes´ us Carretero a a Universidad Carlos III de Madrid, Computer Science Department, Legan´ es, Madrid 28911, Spain b Barcelona Supercomputing Center, Computer Applications in Science & Engineering, Barcelona 08034, Spain Abstract The work we present in this paper focuses on understanding the propa- gation of flu-like infectious outbreaks between geographically distant regions due to the movement of people outside their base location. Our approach incorporates geographic location and a transportation model into our exist- ing region-based, closed-world EpiGraph simulator to model a more realis- tic movement of the virus between different geographic areas. This paper describes the MPI-based implementation of this simulator, including several optimization techniques such as a novel approach for mapping processes onto available processing elements based on the temporal distribution of process loads. We present an extensive evaluation of EpiGraph in terms of its ability to simulate large-scale scenarios, as well as from a performance perspective. Keywords: * Corresponding author Email addresses: gmcruz@arcos.inf.uc3m.es (Gonzalo Mart´ ın), desingh@arcos.inf.uc3m.es (David E. Singh), maria.marinescu@bsc.es (Maria-Cristina Marinescu), jcarrete@arcos.inf.uc3m.es (Jes´ us Carretero) Preprint submitted to Elsevier April 27, 2014