On Tue, Jun 2, 2015 at 8:21 AM, David Collins <dcollins4096@gmail.com> wrote:
Hi, Everybody--

This was discussed a while back, but I wanted to further clarify, and possibly mooch a script or two off y'all.  

I'd like a PhasePlot from a projected region.  Earlier FRBs were discussed; has anyone successfully done the same on a YTQuadTreeProj?  I'd like to retain all the high resolution data, if possible.  

Cameron, back in Jan you mentioned you had a script.  Did you manage to track it down, and/or would you be willing to send it my way?

This is buried a few layers deep in my code, but I use this to generate radial profiles from an image:


In lieu of a docstring on that function, 'data' is an image, 'weight' is a weight image (if you are doing a weighted profile), and x_bin_edges is a specification for bin edges that should be passed to np.histogram.

On Fri, Jan 16, 2015 at 10:31 PM, John ZuHone <jzuhone@gmail.com> wrote:
This is a bit of a long way around, but you could write the FRB to a FITS file and read it in as a dataset. You would get the coordinate system, units, etc., and the whole YT machinery.

Use the export_fits method:

my_frb.export_fits("myfile.fits", fields)


ds = yt.load("my_file.fits")

I'm not at a computer so I don't remember the exact signature, but it should be in the code and you can check using help(my_frb.export_fits). If you're interested I can write back with more info later.

The other advantage of this is that you can store the data to disk. You'll have to install the AstroPy package.

Kavli Center for Astrophysics and Space Research
Massachusetts Institute of Technology
77 Massachusetts Ave., 37-582G
Cambridge, MA 02139
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(m) 781-708-5004

On Jan 16, 2015, at 8:34 PM, Ben Thompson <bthompson2090@gmail.com> wrote:

Hey guys.

I have a solution together for myself involving the new particle_position_relative_[xyz] fields and multiple instances of np.histogram and np.linspace which seems to do the trick.

Although I would not complain if a piece of code that would be more native to the inner workings of YT existed that made use of the FRB data objects :). So that would be very nice Cameron. Don't feel the need to rush with it though, as I made a numpy solution for myself. But I would be interested to see that code.


On 17 Jan 2015 01:27, "Britton Smith" <brittonsmith@gmail.com> wrote:
Hi Ben,

I seem to recall people on this list doing similar things in the past with their own external code.  Does anyone still have their 2D radial profile code around anymore?

Would it perhaps work to create a uniform grid dataset from an FRB array?


On Tue, Jan 13, 2015 at 12:49 PM, Ben Thompson <bthompson2090@gmail.com> wrote:
Hello everyone.

I was wondering if anyone has had experience with producing a profile plot from a 2d projection object (FRB object).

Essentially, what I am trying to do is plot the stellar surface density of a galaxy as a function of radius.

This is achieved by doing the following from a disk YT object called cylinder (in which the origional simulation object is called shot)

center = cylinder.get_field_parameter("center")
normal = cylinder.get_field_parameter("normal")
image_width = (100,"kpc")
three_image_width = YTArray((image_width[0], image_width[0], image_width[0]),image_width[1])
left = center - image_width
right = center + image_width
region = shot.region(center, left, right)

proj = yt.ProjectionPlot(cylinder.ds,"z",[("deposit","stars_density")],center=center,width=image_width,data_source=region,axes_unit="kpc")

the error arrises here

prof = yt.create_profile(proj,bin_fields="cylindrical_r",fields=[("deposit","stars_density")],n_bins=128,weight_field=None )

where I get the error

/gpfs/home/........./profiles.pyc in create_profile(data_source, bin_fields, fields, n_bins, extrema, logs, units, weight_field, accumulation, fractional)
   1304     else:
   1305         raise NotImplementedError
-> 1306     bin_fields = data_source._determine_fields(bin_fields)
   1307     fields = data_source._determine_fields(fields)
   1308     if units is not None:

AttributeError: 'FixedResolutionBuffer' object has no attribute '_determine_fields'

Any ideas how to get around this error?

Also some other things to add as a postscript. Since how the projection works, if I provide weights=None as a keyword argument within the ProjectionPlot object, I get a surface density (g/cm^2). But also a "cylindrical_r" in cm^2 as well. I *think* the way to get around this is to do another projection where weights="ones", get the radius values out of that profile.. and then in matplotlib, useing the surface density array from the former profile, and the radius bin array from the latter... Produce a plot of the surface density as a function of radius from those two arrays (I might check by hand afterwards to see if this does the trick). This seems kinda convoluted so I am wondering if there is an easier way than this.

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