Charm++ parallel programming system

[Shad Kirmani <sxk5292 AT cse.psu.edu>]

Hi Tom,

The problem was at our end. There was a minor error in our model. After fixing it, the forces are coming out alright. 

We thank you for your time. 

Shad Kirmani

Graduate Student

CSE PSU

On Mon, May 16, 2011 at 11:23 AM, Tom Quinn <trq AT astro.washington.edu> wrote:

What softening did you use?  Did you use periodic boundary conditions? What bucket size did you use?  With so few particles, I would guess that no multipole expansions were used: there would only be a couple of nodes in the tree, and they wouldn't be well separated.

It would be easier to track this down if you provided the param file, the initial condition file, and the command line parameters you used.

Tom Quinn       Astronomy, University of Washington
Internet:       trq AT astro.washington.edu
Phone:          206-685-9009

On Wed, 11 May 2011, Shad Kirmani wrote:

I generate 8-10 particles distributed uniformally(using rand) in space from
(-5,-5) to (5,5). 
I print out the forces calculated by ChaNGa and the order in which they are
calculated.  I verify the force calculations by doing them manually(since
the number of particle is small) and in the same order as ChaNGa. 

I used the default parameters. I ran on a single treepiece. 

Thanks for looking in to this.
Shad Kirmani
Graduate Student
CSE PSU

On Tue, May 10, 2011 at 12:27 PM, Pritish Jetley <pjetley2 AT uiuc.edu> wrote:
     Could you give us a few more details? In particular, it would be
     helpful to have the data set you are using, as well as the
     parameters
     passed to the code. Also, I'd like to know how you made the
     comparison
     of forces. Did you use the output of an N^2 computation as a
     yardstick?

     Thanks,
     Pritish

     P.S.: I have included cosmology-ppl in the list of recipients.
     This is
     the ChaNGa mailing list.

On Tue, May 10, 2011 at 9:42 AM, Shad Kirmani <sxk5292 AT cse.psu.edu>
wrote:
> Hello,
> I have been using your ChaNGa code to calculate forces between the
> particles.
> When it comes to calculating forces there seems to be an issue.
Particle to
> node (using nodeBucketForce in gravity.h) is not being calculated to
the
> correct value. I am not being able to figure out why this is so.
> We printed out the tree and verified that it is correct. We also
verified
> the Centre of Mass for each of the node to be correct.
> Can anyone give me helpful pointers where I might be going wrong?
> Thanks,
> Shad Kirmani
> Graduate Student,
> CSE, Penn State
> _______________________________________________
> charm mailing list
> charm AT cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/charm
>
>



--
Pritish Jetley
Doctoral Candidate, Computer Science
University of Illinois at Urbana-Champaign