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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