FDS has 3 ways you can run:
1. Serial - FDS runs the entire problem in a single process. This is the "normal" way to run when you''re starting out.
2. OpenMP - The FDS code has been instrumented to run various processing loops using multiple threads. This way lets you take advantage of multiple processors on a single computer, but it''s very fine-grained and doesn''t usually give as much speedup as MPI*.
3. MPI - Each mesh is run in a separate process. Processes can be spread out across multiple computers on a network. From data I''ve collected, this generally gives the fastest simulations assuming your meshes are of similar size (cell count).
* - Here is some performance data we collected for different parallel approaches:
http://www.pyrosim.com/benchmarks.html Have a look at the Simulation Run Time table.
PyroSim supports all three modes, but only on a single computer. To take advantage of multiple computers on a network, you''ll need to run FDS by hand. This isn''t really so bad and the process is pretty well explained in the FDS Users Guide, section 3.1.2: Starting an FDS Calculation (Multiple Processor Version).
To get your FDS input file out of PyroSim: On the File menu, click Export, then click FDS File... After exporting the FDS file, follow the instructions in FDS Users Guide to run a parallel problem. When you''re finished, you can run smokeview from the command line, or from within PyroSim -- ultimately both approaches just start smokeview.exe
