Mailman 3 August 2011 - yt-users

data along rays
by Elizabeth Tasker Aug. 9, 2011

Aug. 9, 2011

Hi, I have a mystery: Creating a ray via: ray = pf.h.ray( com[c], com[nearestcore]) and I want to get the effective potential along it, for which I have a subrountine for. However, yr gets stuck here: if data.pf["HydroMethod"] == 2: xvel[0:-1,0:-1,0:-1] = 0.5*(data["x-velocity"][slice(None,-1,None),0:-1,0:-1]+data["x-velocity"][slice(1,None,None),0:-1,0:-1]) I thought the problem was because a ray is a 1D data set and I was trying to treat it like a 3D array, but what confuses me is that: ray["DivV"] works just fine but as the same sort of line within its definition. http://yt.enzotools.org/doc/reference/field_list.html#divv To make matters more confusing, if I copy out the definition of DivV directly from universal_fields.py and implement it imaginatively as DivV2, the code doesn't work, giving me: /1/home/taskere/yt/scripts/iyt in _DivV2(field, data) 211 div_fac = 2.0 212 ds = div_fac * data['dx'].flat[0] --> 213 f = data["x-velocity"][sl_right,1:-1,1:-1]/ds 214 f -= data["x-velocity"][sl_left ,1:-1,1:-1]/ds 215 if data.pf.dimensionality > 1: IndexError: too many indices What magic line does yt have to allow DivV to work for a ray? Thanks, Elizabeth

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slice: quick question
by Elizabeth Tasker Aug. 5, 2011

Aug. 5, 2011

Hi, Simple question, I think. In the definition of divV: http://yt.enzotools.org/doc/reference/field_list.html#divv How is the call for slice working: sl_left = slice(None,-2,None) sl_right = slice(2,None,None) and for Zeus: sl_left = slice(None,-2,None) sl_right = slice(1,-1,None) The documentation says the arguments should be axis & co-ordinate and then some options. I have failed to work out the syntax based on what I know the result must be! Thank you~ Elizabeth

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reading RAMSES files - missing cosmological_simulation flag?
by Rok Roskar Aug. 5, 2011

Aug. 5, 2011

hi there, trying to read a RAMSES output from a cosmological zoom simulation, I get the following perplexing error: >>> from yt.mods import * >>> sim = load("output_00422/info_00422.txt") output_00422/amr_00422.out00001 yt : [INFO ] 2011-08-05 15:13:45,236 Parameters: current_time = -2.10180018413e+16 yt : [INFO ] 2011-08-05 15:13:45,237 Parameters: domain_dimensions = [2 2 2] yt : [INFO ] 2011-08-05 15:13:45,237 Parameters: domain_left_edge = [ 0. 0. 0.] yt : [INFO ] 2011-08-05 15:13:45,238 Parameters: domain_right_edge = [ 1. 1. 1.] yt : [ERROR ] 2011-08-05 15:13:45,238 Missing cosmological_simulation in parameter file definition! this clearly is a cosmological simulation with the relevant parameters specified in the info*.txt file - is something else needed? Thanks, Rok

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Re: [yt-users] velocity fields in yt
by Elizabeth Tasker Aug. 3, 2011

Aug. 3, 2011

Although actually, "RadialVelocity" is one place where it would also be an issue. It doesn't look like that is corrected for Zeus, if x-velocity etc are still face-centred. Am I reading that right? Elizabeth Tasker wrote: > I was wondering if the x-velocity, y-velocity and z-velocity fields > themselves had been averaged to give a cell-centred quantity. There's > no need for them to be so, I just needed to know before I calculated a > cross-product to find the rotational potential of clouds I'd picked out. > > Thank you for the clarification :) > > Elizabeth > > > Matthew Turk wrote: >> Only in the DivV and VoritictySquared fields. Where else should it >> be made? >> >> On Wed, Aug 3, 2011 at 5:04 PM, Elizabeth Tasker >> <taskere(a)mcmaster.ca> wrote: >> >>> Hi, >>> >>> Quick question about the baryon velocity fields in yt: has any >>> correction >>> been made for the fact Zeus uses face-centred, not cell-centred, >>> velocities? >>> >>> Elizabeth >>> _______________________________________________ >>> yt-users mailing list >>> yt-users(a)lists.spacepope.org >>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org >>> >>> >> _______________________________________________ >> yt-users mailing list >> yt-users(a)lists.spacepope.org >> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org >> > > _______________________________________________ > yt-users mailing list > yt-users(a)lists.spacepope.org > http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org

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velocity fields in yt
by Elizabeth Tasker Aug. 3, 2011

Aug. 3, 2011

Hi, Quick question about the baryon velocity fields in yt: has any correction been made for the fact Zeus uses face-centred, not cell-centred, velocities? Elizabeth

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Integration efforts between VisIt and Yt
by Harinarayan Krishnan Aug. 3, 2011

Aug. 3, 2011

Hi Yt users, I am happy to announce that there is an effort underway to integrate Yt and VisIt (http://llnl.gov/visit). Once development is complete, you should be able to utilize VisIt's functionality seamlessly with Yt. We are also in the process of integrating Yt into VisIt. So for any VisIt users out there, the new features should make using VisIt a lot easier, if you are already comfortable with Yt. We would like a second of your time to fill out a quick survey in order to gauge your interest in these efforts. https://spreadsheets.google.com/a/lbl.gov/spreadsheet/viewform?hl=en_US&pli… Please note that there is a feature section where you can sound off on any features that you may have wanted either Yt or VisIt to provide. We would like to see where we can improve Yt, VisIt, or both. Thanks, Hari

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