[yt-users] 1D matter power spectrum

[Matthew Turk]

Hi Geoffrey,

If an FFT would work for your purposes of comparison, you could sample
along rays and then calculate the NUFFT.

-Matt

On Mon, Mar 7, 2011 at 6:10 PM,  <gso at physics.ucsd.edu> wrote:
> Matt, yes that is correct, although the YT one will probably under-sample
> if I don't use enough points, but should not change the answer by too
> much.
>
> Stephen, thanks, this way I'll be able to double check if the IDL script
> that is supposedly calculating the 1D power spectrum is doing the right
> thing :-)
>
> From
> G.S.
>
>
>> Hi Geoffrey,
>>
>> If I understand you correctly, what you would like is to sample many,
>> many axis-aligned rays through the domain, and calculate the 1D power
>> spectrum along each individual ray?
>>
>> -Matt
>>
>> On Mon, Mar 7, 2011 at 6:01 PM,  <gso at physics.ucsd.edu> wrote:
>>> For each of the random point generated, I want to limit their position
>>> to
>>> be on either the x, y or z direction instead of on a sphere, so I can
>>> compare them with the 1D power spectrum.
>>>
>>> For example if I want to compare with the 1D powerspectrum along x, I
>>> want
>>> phi = 0, theta= pi/2
>>> if I want to compare to z, then
>>> phi = *, theta = pi/2
>>>
>>> is this ability already in YT or can it be added easily?
>>>
>>> From
>>> G.S.
>>>
>>>> Geoffrey,
>>>>
>>>>> is there a way to limit the random total_values of pts generated for
>>>>> say
>>>>> (r, theta, phi) in the physics convention?
>>>>>
>>>>> x = (phi = 0, theta = pi/2)
>>>>> y = (phi = pi/2, theta = pi/2)
>>>>> z = (phi = *, theta = 0)
>>>>
>>>>
>>>> I am sorry, but I don't understand what you mean. "total_values" is
>>>> just
>>>> the absolute number of point pairs generated. Are you referring to the
>>>> range of x,y,z values generated for points? If so, I still don't
>>>> understand what you mean with phis and thetas.
>>>>
>>>> In summary, random points are created as follows. For a given length r
>>>> (separation between the two points):
>>>>
>>>> 1. Create a random point inside the volume (or subvolume if running in
>>>> parallel).
>>>> 2. Make a random angle (theta, phi), go out r in that direction to find
>>>> the second point.
>>>>
>>>> What is it you want to do?
>>>>
>>>>
>>>> Stephen Skory
>>>> stephenskory at yahoo.com
>>>> http://stephenskory.com/
>>>> 510.621.3687 (google voice)
>>>>
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