CFD Online Logo CFD Online URL
Home > Forums > Phoenics

Problems in Parallel PHOENICS

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   February 22, 2001, 09:52
Default Problems in Parallel PHOENICS
Posts: n/a
I have encountered problems list below in parallel PHOENICS, any of your sugestion is appreciated. (1) phi file size is different between the simulation with single- and multi-CPU. (2)The simulation seems ok for the 401 case in VR library with single CPU, but the simulation is divergent by the parallel PHOENICS with multi-CPU, and of course its result is unbelievable. (3)I have coded ground.f, it works well for single CPU simulation, but it does not work after parallelisation. These is no error to build paraear, but the simulation seems to be suspended when it runs.

Has any one here experienced same problem in parallel PHOENICS? How do you overcome these problems? Is there any rules for coding ground.f with parallel calculation?

Thanks in advance

  Reply With Quote

Old   February 22, 2001, 13:38
Default Re: Problems in Parallel PHOENICS
George Bergantz
Posts: n/a
I am running parallel PHOENICS and can perhaps provide a few useful comments. I may be dead wrong about some of these things, but here is what I've come to understand:

1) The phi file is only for the first processor. Each processor creates its own restart file. Hence visualization of the entire domain cannot be done with say PHOTON. Again, I may be wrong about this.

2) I can't help you with the divergence issues. Be sure that you appreciate that re-gridding to a higher number of nodes, as we often do to exploit the power of parallel, can impact convergence. But that may not be your problem.

3) If you are using MPI it is my understanding and experience that you cannot simply code ground.f as you would with a sequential algorithm. You must be mindful of coding and compilation in the context of the MPI commands and framework. That is too extensive a topic to be treated here, perhaps a CHAM engineer can weigh-in on that point. I have been given example ground files that CHAM has written for specific parallel problems where the source terms have been parallelized, and things are a bit different than the usual approach. For one thing you are working in the X or Y to Z plane so the usual GETYX, SETYX and other niceities of grabbing things from the F array are now moot.
  Reply With Quote

Old   February 22, 2001, 22:40
Default Re: Problems in Parallel PHOENICS
Posts: n/a
Hi, George

Thanks. If it is possible, can I have a look at the example ground file, which you received from CHAM. I have sent my groud and q1 files to their agent two weeks before, and I am waiting their reply.

Thank again,

  Reply With Quote

Old   February 27, 2001, 14:28
Default Re: Problems in Parallel PHOENICS
Sandeep Karode
Posts: n/a
I have encountered similar problems too!
  Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Restart of variables in parallel phoenics RJD Phoenics 1 April 25, 2009 23:34
Runing Parallel PHOENICS J.S.8a Phoenics 0 November 28, 2002 09:06
About parallel in phoenics Bryan Lam Phoenics 6 December 27, 2001 01:54
How to run his phoenics in parallel mode? Bryan Lam Phoenics 3 December 19, 2001 10:43
parallel PHOENICS George Bergantz Phoenics 9 November 16, 2000 16:57

All times are GMT -4. The time now is 16:49.