Intel Trace Collector MPI issues

You can use the Intel Trace Collector to check for the correctness of MPI calls, so I thought I'd try that out to see if it helped with #34 (closed).

The setup on COSMA is to load the Intel modules needed to build SWIFT and then do:

source /cosma/local/intel/Parallel_Studio_XE_2015/parallel_studio_xe_2015/psxevars.csh
setenv VT_CHECK_TRACING on

(use .sh and export for bash) and then run the application using the -check_mpi flag, as in:

mpirun -check_mpi -np 3 ../test_fixdt_mpi -r 1000 -t 12 -f SodShock/sodShock.hdf5 -m 0.01 -w 5000 -d 1e-4 -g "1 3 1"

For reference, you can tune which warnings and errors you get using an environment variable like:

setenv VT_CHECK "LOCAL:MEMORY:ILLEGAL_MODIFICATION OFF LOCAL:REQUEST:NOT_FREED OFF"