Understanding parallel solvers

milkovp · May 15, 2008, 17:20

Dear all,
I am trying to understand how the parallelisation is done in Openfoam. But in applications/solvers/multiphase/interFoam/interFoam.C (and included files) I don't find the slightest hint of any MPI calls, although the interFoam/damBreak tutorial can be run in parallel.

Would you give me a rough overview which function calls finally lead to the parallel communication, and which source file is responsible for coordinating the parallel work?

Thank you
Pavel

gschaider · May 15, 2008, 19:43

Hi Pavel!

The actual MPI(or equivalent)-calls are encapsulated by the PStream-library. Have a look there.

Bernhard

milkovp · May 16, 2008, 13:51

Thank you Bernhard!
While browsing through the sources I thought Openfoams PStream library was a special version of http://pstreams.sourceforge.net/, so I didn't recognize the real purpose.

But there is no relationship at all between the two, is it?

Do the Openfoam sources happen to be documented in more detail than the Programmer's guide and other than the Doxygen output? The Doxygen output is useful to understand class hierarchies, but because (afaik) it only parses the header files, it doesn't help to follow the program flow across the classes.
I would need some kind of flow diagram, representing the whole bunch of sources by a few blocks which group related functionality, so that a typical application like the parallel damBreak example could be more easily comprehended from a visual representation. Do you know any technical Openfoam documentation including such an overview, especially about the parallelism?

Pavel

gschaider · May 20, 2008, 17:07

Hi Pavel!

@Doxygen: It is possible to have Doxygen parse the .C files and even generate HTML-files for each of them that are interlinked with the class docu. I don't know the name of Flag that switches that on, but it should be rather obvious whern you have a look at the Doxyfile that comes with the distributed Doxygen-docu (but of course doxygen will take its time to generate the new files)

@Additional docu: Some additional info can be found at: http://www.mfix.org/mwiki/index.php/...d_Capabilities

Bernhard

May 15, 2008, 17:20	Dear all, I am trying to unde	#1
milkovp New Member P. Milkov Join Date: Mar 2009 Posts: 5 Rep Power: 17	Dear all, I am trying to understand how the parallelisation is done in Openfoam. But in applications/solvers/multiphase/interFoam/interFoam.C (and included files) I don't find the slightest hint of any MPI calls, although the interFoam/damBreak tutorial can be run in parallel. Would you give me a rough overview which function calls finally lead to the parallel communication, and which source file is responsible for coordinating the parallel work? Thank you Pavel

May 15, 2008, 19:43	Hi Pavel! The actual MPI(or	#2
gschaider Assistant Moderator Bernhard Gschaider Join Date: Mar 2009 Posts: 4,225 Rep Power: 51	Hi Pavel! The actual MPI(or equivalent)-calls are encapsulated by the PStream-library. Have a look there. Bernhard __________________ Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request

May 16, 2008, 13:51	Thank you Bernhard! While bro	#3
milkovp New Member P. Milkov Join Date: Mar 2009 Posts: 5 Rep Power: 17	Thank you Bernhard! While browsing through the sources I thought Openfoams PStream library was a special version of http://pstreams.sourceforge.net/, so I didn't recognize the real purpose. But there is no relationship at all between the two, is it? Do the Openfoam sources happen to be documented in more detail than the Programmer's guide and other than the Doxygen output? The Doxygen output is useful to understand class hierarchies, but because (afaik) it only parses the header files, it doesn't help to follow the program flow across the classes. I would need some kind of flow diagram, representing the whole bunch of sources by a few blocks which group related functionality, so that a typical application like the parallel damBreak example could be more easily comprehended from a visual representation. Do you know any technical Openfoam documentation including such an overview, especially about the parallelism? Pavel

May 20, 2008, 17:07	Hi Pavel! @Doxygen: It is p	#4
gschaider Assistant Moderator Bernhard Gschaider Join Date: Mar 2009 Posts: 4,225 Rep Power: 51	Hi Pavel! @Doxygen: It is possible to have Doxygen parse the .C files and even generate HTML-files for each of them that are interlinked with the class docu. I don't know the name of Flag that switches that on, but it should be rather obvious whern you have a look at the Doxyfile that comes with the distributed Doxygen-docu (but of course doxygen will take its time to generate the new files) @Additional docu: Some additional info can be found at: http://www.mfix.org/mwiki/index.php/...d_Capabilities Bernhard __________________ Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request

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