Dimemas external communications model support
=============================================

Dimemas offers a simple interface to compute the duration of the p2p and
collective communications externally.

*** Implementation of the external communications model library ***

In brief, you have to implement the 5 functions declared in the file
'external_comm_model.h', located in $DIMEMAS_HOME/include directory, and
compile this source code as a shared object (.so file in Linux kind systems).
In this header file there is a detailed description of the semantics of each
of the functions.

To implement your own version of the external communication library you can
follow the example given in the present directory.

*** Using the external communications model library ***

To indicate the Dimemas simulator that a external communications model
library can be used, you have to set an environment variable named 
DIMEMAS_EXTERNAL_COMM_LIBRARY, that points to the shared object that contains
it. In the initialization, the simulator will check if all the required
symbols have been declared, and then it will the different functions as
explained below.

