CFD Online URL
[Sponsors]
Home > Forums > OpenFOAM

Questions about OpenFOAM

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 29, 2008, 04:47
Default Hi, I am new to OpenFOAM an
  #1
New Member
 
Michael Schroeter
Join Date: Mar 2009
Location: Germany
Posts: 4
Rep Power: 7
misch is on a distinguished road
Hi,

I am new to OpenFOAM and I have some questions about using OpenFOAM. But I am not shure if the has been asked already before. Sorry, for that.

* Is there a possibilitiy/switch to get single cpu I/O (or single file I/O) for multi-cpu jobs?

* Is there a way to get some accumulated timing informations at the end of running an OpenFOAM application? I am interested in execution times of
different parts of the code (e.g. i/O, inter
process communication, initialisation, finalisation, solver). For the solver part time consumption is printed to screen after each time step. This is not what I want. I need more detailed informations.

* My last question is of more general nature and is about parallelisation technique used in FOAM. As far as I understand FOAM is parallelised using MPI (several MPI implementations are possible to use). But what about OpenMP or shared memory features in general? Are they planed for the future? Multi core architectures become more and more important, especially in high end HPC.

Thanks and best regards
Michael
misch is offline   Reply With Quote

Old   August 29, 2008, 05:15
Default Hello Michael, 1) single CP
  #2
Senior Member
 
Hrvoje Jasak
Join Date: Mar 2009
Location: London, England
Posts: 1,748
Rep Power: 20
hjasak will become famous soon enough
Hello Michael,

1) single CPU output: Yes, write just from processor zero. Field data will still be in pieces, but you can reconstruct this easily.

2) timing information: Yes, there is a bit called cpuTimeIncrement, but you will have to add the statements to various parts of the code to time them separately. This will allow you to time the bits you want.

3) OpenMP: Yes, but this has not been done. I believe OpenMP will sort out our multi-core CPU problems, but this requires surgery at bottom-level of containers and some careful work. Do you have experience with this?

Hrv
__________________
Hrvoje Jasak
Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk
hjasak is offline   Reply With Quote

Old   August 29, 2008, 06:18
Default Hi Hrv, many thanks for you
  #3
New Member
 
Michael Schroeter
Join Date: Mar 2009
Location: Germany
Posts: 4
Rep Power: 7
misch is on a distinguished road
Hi Hrv,

many thanks for your quick response.

1) single CPU ouput: is there a switch to add to
controlDict?

2) ok!

3) Concerning OpenMP: I have only some basic experience in openmp (fortran) programming but not in c/c++ (Sorry, innately I am a fortran programmer). But I know that shared memory programming or hybrid programming respectively is an important issue for the furture development of cdf codes in general. Particularly to reach good scalability on multi-core-multi-node machines.

Best
Michael
misch is offline   Reply With Quote

Reply

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
OpenFoam vs CFX5 mass balance in OpenFoam tangd OpenFOAM Running, Solving & CFD 33 May 23, 2010 17:36
CheckMesh error using a tutorial from OpenFOAM 114 with openFOAM 13 martapajon OpenFOAM Native Meshers: blockMesh 7 January 21, 2008 13:52
OpenFOAM users in Munich OpenFOAM benutzer in M%c3%bcnchen jaswi OpenFOAM 0 August 3, 2007 14:11
Questions for the bdivb function in OpenFOAM gkang OpenFOAM Running, Solving & CFD 3 May 13, 2006 12:11
A new Howto on the OpenFOAM Wiki Compiling OpenFOAM under Unix mbeaudoin OpenFOAM Installation 2 April 28, 2006 09:54


All times are GMT -4. The time now is 14:47.