[yt-users] yt for RAMSES

[Nicolas Gillet]

Hi Ricarda,

first I hope I answer at the right place...

- for the field issue it does not work :
ad['all','star_age2'] and ad[('all','star_age2')] give the same error =>YTFieldTypeNotFound: Could not find field 'all'.
But I can see in the derived_field_list('all', 'star_age2') and even('star', 'star_age2'), with 'star' my particle filter!

I have made the update to 3.3-dev

Nicolas







Hi Nicolas,

the star ages are indeed a known and unsolved problem in yt when using RAMSES.

Having a quick look at your code it seems fine, you just need one more set of brackets when calling it: ad[('all',’star_age2’)]
Otherwise it looks for the fields “all” and “star_age2” separately.

Does that help?

Ricarda

>/  On 14 Jan 2016, at 14:03, Nicolas Gillet <nicolas.gillet at etu.unistra.fr  <http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org>> wrote:
/>/  
/>/  Hello,
/>/  
/>/  I am Nicolas, I am a new YT user. I am working on RAMSES simulations.
/>/  
/>/  - First I have noted a "bug" (or misunderstand) in the yt.load of RAMSES data.
/>/  It takes all the times of the output as 'code_units' times, which is not the case.
/>/  The output times are negative and I think it needs a FLRW integration to be converted in conventional time.
/>/  Using directly the 'code_units_time' to convert in cgs time is wrong.
/>/  So all the times are false in the loaded yt data, simulation time, particles ages ....
/>/  
/>/  - My second question is link to the first point. With ramses there is a tool (getstarlist.f90) that extract only the stars in a .txt file, with the ages in Myr with the proper conversion.
/>/  My idea is to load those new data in yt, and creat a new field for particles, with this correct ages.
/>/  With the example I creat a filter to isolate the stars from 'all' particles, and it apear in the derived_field_list.
/>/  But I do not find a way to creat a new field for this filtered particles and even for the 'all' particles.
/>/  
/>/  I would like to have the possibility to have a field ad['star', 'my_own_ages'] or ad['all', 'my_own_ages'].
/>/  
/>/  What I have done:
/>/  
/>/  ### isolate star particles
/>/  def _star(pfilter, data):
/>/      filter = data['all', 'particle_age'] < 0
/>/      return filter
/>/  
/>/  add_particle_filter('star', function=_star, filtered_type='all', requires=['particle_age','particle_identifier'])
/>/  ds.add_particle_filter('star')
/>/  
/>/  ### stars are correctly created ok
/>/  
/>/  ### create a global star_age field, not linked to 'all' or 'star'
/>/  def _star_age(field, data):
/>/      T = data['particle_age'].in_units('Myr') * 0.
/>/      selec_stars = np.where(data['particle_age'] < 0)[0]
/>/      T[selec_stars] = Stars[5,:] * yt.units.Myr
/>/      return T
/>/  
/>/  ds.add_field('star_age', function=_star_age, units='Myr')
/>/  
/>/  
/>/  
/>/  What I try:
/>/  
/>/  def _star_age2(field, data):
/>/      T = data['all','particle_age'].in_units('Myr') * 0.
/>/      selec_stars = np.where(data['all','particle_age'] < 0) [0]
/>/      T[selec_stars] = Stars[5,:] * yt.units.Myr
/>/      return T
/>/  
/>/  ds.add_field(('all','star_age2'), function=_star_age2, units='Myr')
/>/  
/>/  ### ('all','star_age2') appear in the derived_field_list but
/>/  
/>/  ad['all','star_age2'] => YTFieldTypeNotFound: Could not find field 'all'
/>/  
/>/  
/>/  Thank you for your help,
/>/  Nicolas/

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