[parsec-users] extending input set for fluidanimate

Jim Dempsey jim at quickthreadprogramming.com
Thu Mar 25 18:13:12 EDT 2010


Chris, Kirak,
 
For benchmarking I think the 500K is more than adequate for 1P or 2P
systems. 500K x 104 = ~50MB data. On 4P or 8P systems 500K particles could
fit in cache (at 12/24MB per processor). A larger data set would be
appropriate for these systems. I could see a need to generate 1M, 2M, 4M, 8M
and 16M particles. So I think a feature should be incorporated into
fluidanimate (or application added) whereby the domain dimensions, cell size
and and number of particles be specified, and then which will generate a
test data set.
 
An alternate way to accomplish this auto-magically, would be for the initial
particle domain dimensions, cell size and particle count, be
duplicated/multiplied as an input option. The additional particle domains
would then be abutted together. Example,
 
The 55 cell x 76 cell x 55 cell domain can be (by option) specified to be
doubled, thus producing
110 cell by 76 cell x 55 cell particle domain, or quadrupled, thus producing
110 cell by 76 cell x 110 cell particle domain.
 
The 76 cell Y is along the direction of gravity and would likely not need to
be extended.
The trailing options could be x, y, and z multipliers
 
serial 1 0 in_500k.fluid in_2M.fluid 2 1 2 
 
Run Serial.exe, 1 thread, 0 frames, input file in_500k.fluid, output file
in_2M.fluid, dimension x doubled, dimension y unchanged, dimension z
doubled.
 
Or the user could simply run with the multipliers and smaller input file
 
This has as an additional benefit of being able to ship PARSEC with smaller
data files.
 
Jim
 

  _____  

From: parsec-users-bounces at lists.cs.princeton.edu
[mailto:parsec-users-bounces at lists.cs.princeton.edu] On Behalf Of Christian
Bienia
Sent: Thursday, March 25, 2010 3:40 PM
To: 'PARSEC Users'
Subject: Re: [parsec-users] extending input set for fluidanimate



Kirak,

 

Jim's suggestion should give you a good input with not too much work.
Another approach would be to write a synthetic input generator that will
generate random inputs with any amount of particles. You need to vary the
initial position and velocity of the particles. You also must make sure that
particles start within the bounding box and do not initially move too fast,
otherwise the simulation will become numerically unstable. The upper bound
on the velocity is given by the grid size and the time step size.

 

If you use significantly more particles you might want to consider to
increase the volume of the bounding box. The particles should fit in
comfortably.

 

Why exactly do you want bigger inputs?

 

- Chris

 

 

From: parsec-users-bounces at lists.cs.princeton.edu
[mailto:parsec-users-bounces at lists.cs.princeton.edu] On Behalf Of Jim
Dempsey
Sent: Thursday, March 25, 2010 3:48 PM
To: 'PARSEC Users'
Subject: Re: [parsec-users] extending input set for fluidanimate

 

Kirak,

 

More than 500K particles?

 

If so, as a quick and dirty "hack", edit the SaveFile such that it doubles
the particle count and writes each particle twice. Run the in_500K.fluid in,
and write out in_1M.fluid. Repeat this to double the particle counts.
Probably it would be best to add an additional argument to specify the
multiplier (and so you do not have to remember to remove the"hack"). You
might want to add a randomizer to the point duplicator such that no two
particles come in at exactly the same position. You might want to keep the
replicated particles within a reasonably close position. Should the
resultant file cause an explosion in the particles (blast out of the bottom
of the domain well) you can use the display mode and let the simulation run
until it has quieted down somewhat (but not all the way). Then reset the
simulation without display to run to that frame number. The output file is
now a reasonable approximation of what you might want.

 

Jim Dempsey.

 

  _____  

From: parsec-users-bounces at lists.cs.princeton.edu
[mailto:parsec-users-bounces at lists.cs.princeton.edu] On Behalf Of Kirak Hong
Sent: Thursday, March 25, 2010 2:35 PM
To: parsec-users at lists.cs.princeton.edu
Subject: [parsec-users] extending input set for fluidanimate

Hi,

I am trying to make more input data set for fluidanimate in parsec 2.1.
I tried to find out input format and how to generate extra input data, but
didn't find anything yet.
Has anybody tried this before? Any help would be highly appreciated!

Thanks!
Kirak

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