example mem-factor configuration in example program

doc/example/example.conf

@@ -25,6 +25,11 @@ PARAMS
    #                 Going over this size will crash or otherwise destroy your 
    #                 simulation.
    message_size="256";
+   # - pe_mem_factor: this is a multiplier to the event memory allocation that
+   #                  ROSS does up front (multiplier is per-PE). Increase this 
+   #                  (or change the associated mem_factor variable in
+   #                  codes-base) if you have a (very) large event population.
+   pe_mem_factor="512";
    # model-net-specific parameters: 
    # - individual packet sizes for network operations
    #   (each "packet" is represented by an event)