[yt-users] Particle only plots

[Sam Skillman]

Hi Jeremy,

I just issued a PR that adds a bit of functionality you might be interested
in.  Check it out here:
https://bitbucket.org/yt_analysis/yt/pull-request/887/color-splatting/diff

You can use it like this:
Npix = 1024
image = np.zeros([Npix, Npix, 4], dtype='float64')

cbx = yt.visualization.color_maps.mcm.Reds
field = (... insert code here to get some floating point array to act as a
color ... )

# Calculate image coordinates ix and iy based on what your view width is

ix = data['particle_position_x'] * (SOME SCALING/SHIFT)
ix = data['particle_position_y'] * (SOME SCALING/SHIFT)

col_field = (col_field - col_field.min()) / (col_field.max() -
col_field.min())
add_rgba_points_to_image(image, ix.astype('float64'), iy.astype('float64'),
cbx(col_field))

yt.write_bitmap(image, 'all_channels.png')
# OR
yt.write_bitmap(image[:,:,:3], 'no_alpha.png')

I need to document this and all that, but I'd like feedback on it if you
have luck with it!  I hope to turn it into a more fully-fledged piece of yt
soon.

Cheers,
Sam


On Wed, May 7, 2014 at 7:11 PM, Andrew Myers <atmyers2 at gmail.com> wrote:

> Hi Jeremy,
>
> I happened have a script that does this. Something like this should work
> (in 2.6):
>
>     from yt.mods import *
>     import pylab as plt
>
>     fn =
> 'Chombo/releasedExamples/AMRParticleMesh/exec/output/plt256.2d.hdf5'
>     pf = load(fn)
>
>     data = pf.h.all_data()
>
>     x = data['particle_position_x']
>     y = data['particle_position_y']
>
>     plt.plot(x, y, '.')
>     plt.savefig('scatter')
>
> -Andrew
>
>
> On Wed, May 7, 2014 at 5:12 PM, Nathan Goldbaum <nathan12343 at gmail.com>wrote:
>
>> Hi Jeremy,
>>
>> Right now there isn't a way to do that in yt.  That's something that
>> would be very nice to add and would probably be a good introductory yt
>> project for someone who wanted to get more familiar with the codebase.
>>
>> What you *can* do is take the particle data and plot the positions in a
>> scatter plot using matplotlib.
>>
>> Unfortunately I don't have a good example of that right now, but it
>> should be pretty straightforward.  You just need to read in the x and y
>> particle position fields and then make a scatter plot using e.g.
>> pyplot.plot().
>>
>> -Nathan
>>
>>
>> On Wed, May 7, 2014 at 4:32 PM, Jeremy Ritter <
>> jritter at astro.as.utexas.edu> wrote:
>>
>>> Hello yt,
>>>
>>> Is there an easy way to plot only particles? What I would like to do is
>>> plot a z-axis projection of particle x/y positions, with no background data
>>> loaded from the grid. I only see examples for annotate_particles() on top
>>> of another plot, but I don't want to unnecessarily load grid data.
>>>
>>> Thanks!
>>> -Jeremy
>>> _______________________________________________
>>> yt-users mailing list
>>> yt-users at lists.spacepope.org
>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>
>>
>>
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