Mailman 3 Generic UniGrid Data - yt-users

16 May 2014

      Dear yt user,

I try to use Generic UnicGrid Data (256^3 gas density cube + position
of particle that is subset of a huge simulation).
It is preliminary work, but I still have some questions.

1. In order to set density unit as cgs, I made following script:
......
data = dict(density = (map, "g/cm**3"))  #map is 256^3 density data array
bbox = np.array([[0., boxsize], [0., boxsize], [0.,boxsize]])
ds = load_uniform_grid(data, data['density'][0].shape, 3.086e24,
bbox=bbox, nprocs=4)
.....

Then, I got the following error message:
Traceback (most recent call last):
  File "cutout2.py", line 62, in <module>
    ds = load_uniform_grid(data, data['density'][0].shape, 3.086e24,
bbox=bbox, nprocs=4)
  File "/Users/jhchoi/common/lib/python2.7/site-packages/yt-3.0dev-py2.7-macosx-10.4-x86_64.egg/yt/frontends/stream/data_structures.py",
line 461, in load_uniform_grid
    psize = get_psize(np.array(data[key].shape), nprocs)
AttributeError: 'tuple' object has no attribute 'shape'

Hence, I modify "data = dict(density = (map, "g/cm**3"))" --> "data =
dict(density = map)" and it work.
If this is the case, how can I define the density unit and show it
when I make Slice/Projection?
In addition, I would like to know how I can set the unit in Generic
UnicGrid Data in general?
The length unit can be provide to script in load_uniform_grid(...
3.086e24 ....) but I do not know how to set other units.

2. When I add particle information as follow:
.....
npart = 100000  # number of particles
data = dict(density = map,
            number_of_particles = npart,
            particle_position_x = posx,
            particle_position_y = posy,
            particle_position_z = posz)
bbox = np.array([[0., boxsize], [0., boxsize], [0.,boxsize]])
ds = load_uniform_grid(data, data['density'][0].shape, 3.086e24,
bbox=bbox, nprocs=4)
...

I got the following error message:
Traceback (most recent call last):
  File "cutout.py", line 107, in <module>
    ds = load_uniform_grid(data, data['density'][0].shape, 3.086e24,
bbox=bbox, nprocs=4)
  File "/Users/jhchoi/common/lib/python2.7/site-packages/yt-3.0dev-py2.7-macosx-10.4-x86_64.egg/yt/frontends/stream/data_structures.py",
line 519, in load_uniform_grid
    assign_particle_data(spf, pdata)
  File "/Users/jhchoi/common/lib/python2.7/site-packages/yt-3.0dev-py2.7-macosx-10.4-x86_64.egg/yt/frontends/stream/data_structures.py",
line 371, in assign_particle_data
    pdata.pop("number_of_particles")
KeyError: 'number_of_particles'

So, I change "number_of_particles = npart," --> "number_of_particles =
100000," and it works.
How could it happen?

3. Can I do halo finder (hop/fof) using the above particle data?
Or, what information do I need to provide to do grouping?
In this case, how can I set the units and linking length?

4. Can I make particle distribution to particle data like
data['Dark_Matter_position_x']?
This process will allow me additional analysis such as profile and
obtaining total value.

I may ask too many for new tool, but it will help a lot to use yt for
general data set.

Thank you,
Junhwan

Generic UniGrid Data

Junhwan Choi (최준환)

Nathan Goldbaum

Junhwan Choi

John ZuHone

Junhwan Choi (최준환)

Junhwan Choi (최준환)

John ZuHone

Nathan Goldbaum

John ZuHone

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participants (4)