[Paraview] Paraview 4.4 Openfoam native reader decomposed read issue

[Takuya OSHIMA]

Hi Leonard,

I am not using OpenFOAM recently so this is what I can only answer:

> Is pvserver (when
> run in parallel) smart enough to not open every data file on every process for
> the native openfoam reader, but to smartly allocate the directories to
> different instances?

Yes. For the allocation strategy, see slide 7 of [1]. And if you
choose "Reconstructed Case" and if the reader still works as intended,
the whole recousructed case should be loaded only by process 0.

[1] http://www.opencae.jp/data/OpenSourceCAEWorkshop/200811/slides/OpenSourceCAEWorkshop200811Ohshima2.pdf

Takuya OSHIMA, Ph.D.
Faculty of Engineering, Niigata University
8050 Ikarashi-Ninocho, Nishi-ku, Niigata, 950-2181, JAPAN

From: Leonard Cassady <lenny at intuitivemachines.com>
Subject: [Paraview] Paraview 4.4 Openfoam native reader decomposed read issue
Date: Wed, 23 Dec 2015 16:33:50 -0600

> Hi,   
> 
>   I've recently upgraded to Openfoam 3.0 and installed paraview 4.4.  To speed
> up reading, I'm using pvserver in parallel (with mpirun) and open the openfoam
> solution with the native openfoam reader as a "decomposed case".  
>   I was able to visualize scalar data as expected.  I was not able to render
> the vector velocity data "U".   It just doesn't show up as an option for
> coloring surfaces or to apply filters to.  Is this a bug in paraview, or am I
> doing something wrong? 
> 
>   Above is my main question.  Below are general questions regarding paraview
> performance. 
> 
>   As you may know, Openfoam creates directories for each processor (say 192)
> when solving the case in parallel. It requires the user to run the same number
> of parallel processes (mpirun -np 192 <openfoamsolver> -parallel)  as there
> are processor directories.  Does pvserver require the user to also run the
> same number of processes as there are processor directories? Is pvserver (when
> run in parallel) smart enough to not open every data file on every process for
> the native openfoam reader, but to smartly allocate the directories to
> different instances?  (I know that if I open a "reconstructed case" with
> pvserver running in parallel each instance of pvserver opens the same file and
> greatly slows the system and overloads ram.)  
> 
>    I believe that my computer has good enough graphics processors to handle
> rendering.  Once I load in a data set I can re-orient and re-color and slice
> very fast.  I also believe that I can open and read the data files quickly (
> about 230 MB/s read rate for my large files).  I believe that the slowest part
> of my data processing is the step between reading and rendering.  It also
> takes a long time to apply complicated filters like stream lines.  How can I
> speed up this part of my visualization?  I have multiple computers and one of
> them is much faster at analysis and I can't figure out why.  
>   
> 
> --
> Leonard Cassady PhD
> Senior Development Engineer
> Intuitive Machines
> Cell: 281-755-2553 
>