[yt-users] Volume Rendering and Memory usage

[Matthew Turk]

Hi Andrew,

That's an odd bug!  Do you think you could get a backtrace from the
segfault?  You might do this by setting your core dump ulimit to
unlimited:

[in base]

ulimit -c unlimited

[in csh]

limit coredumpsize unlimited

and then running again.  When the core dump gets spit out,

gdb python2.6 -c that_core_file
bt

should tell us where in the code it died.  Sam Skillman should have a
better idea about any possible memory issues, but the segfault to me
feels like maybe there's a roundoff that's putting it outside a grid
data array space or something.

Sorry for the trouble,

Matt

On Tue, Feb 1, 2011 at 11:13 PM, Andrew Myers <atmyers at berkeley.edu> wrote:
> Hello yt users,
>
> I'm trying to volume render an Orion simulation with about 6,000 grids and
> 100 million cells, and I think I'm running out of memory. I don't know if
> this is large compared to other simulations people have volume rendered
> before, but if I set the width of my field of view to be 0.02 pc (20 times
> smaller than the entire domain), the following code works fine. If I set it
> to 0.04 pc or anything larger, the code segfaults, which I assume means I'm
> running out of memory. This happens no matter how many cores I run on -
> running in parallel seems to be speed up the calculation, but not increase
> the size of the domain I can render. Am I doing something wrong? Or do I
> just need to find a machine with more memory to do this on? The one I'm
> using now has 3 gigs per core, which strikes me as pretty solid. I'm using
> the trunk version of yt-2.0. Here's the script for reference:
>
> from yt.mods import *
>
> pf = load("plt01120")
>
> dd = pf.h.all_data()
> mi, ma = na.log10(dd.quantities["Extrema"]("Density")[0])
> mi -= 0.1 ; ma += 0.1 # To allow a bit of room at the
> edges
>
> tf = ColorTransferFunction((mi, ma))
> tf.add_layers(8, w=0.01)
> c = na.array([0.0,0.0,0.0])
> L = na.array([1.0, 1.0, 1.0])
> W = 6.17e+16 # 0.02
> pc
>
> N = 512
>
> cam = Camera(c, L, W, (N,N), tf, pf=pf)
> fn = "%s_image.png" % pf
>
> cam.snapshot(fn)
>
> Thanks,
> Andrew Myers
>
>
>
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