Monday, April 13, 2015

FDS 6.2.0 released

We just posted a release of FDS 6.2.0. This is a minor release, meaning that you can expect to see some changes in model results due to minor changes in various algorithms. We would urge you to finish out existing projects or studies with your current version and then upgrade to 6.2 as soon as you can. The reason why is that when bugs are reported for older versions, there is nothing we can do until the bug is observed in the latest version.

A significant change in this release is that there is now only one FDS executable for each of the three operating systems we support, Windows, Linux, and Mac OS X. Thus if you type "fds" or the old "fds_mpi", you will be issuing the same command. OpenMP and MPI are built in to this single executable and we urge you to take a look at the FDS User's Guide chapter called "Running FDS". There has been considerable confusion about OpenMP and MPI, and hopefully this new chapter will help clear some of it up. FDS still works like it always has from the command line if you just type

fds job_name.fds

but there are now a number of options you have to make the job run faster.

One other thing to note is that in the Windows release, we have switched from an older MPI scheduler to the one that is currently maintained by Intel. That is, when you run an MPI calculation by issuing the mpiexec command, you are using a newer version of the scheduler called "hydra_service". Those of you who are curious what this is, just do an Internet search. You should not notice a change in functionality from what we were doing in the last release, 6.1.2; it's just that a different background process will be running. Let us know as soon as possible if you notice anything different about the MPI on Windows.