yt.analysis_modules.cosmological_observation.cosmology_splice module

CosmologyTimeSeries class and member functions.

class yt.analysis_modules.cosmological_observation.cosmology_splice.CosmologySplice(parameter_filename, simulation_type, find_outputs=False)[source]

Bases: object

Class for splicing together datasets to extend over a cosmological distance.

create_cosmology_splice(near_redshift, far_redshift, minimal=True, max_box_fraction=1.0, deltaz_min=0.0, time_data=True, redshift_data=True)[source]

Create list of datasets capable of spanning a redshift interval.

For cosmological simulations, the physical width of the simulation box corresponds to some Delta z, which varies with redshift. Using this logic, one can stitch together a series of datasets to create a continuous volume or length element from one redshift to another. This method will return such a list

Parameters:
  • near_redshift (float) – The nearest (lowest) redshift in the cosmology splice list.
  • far_redshift (float) – The furthest (highest) redshift in the cosmology splice list.
  • minimal (bool) – If True, the minimum number of datasets is used to connect the initial and final redshift. If false, the list will contain as many entries as possible within the redshift interval. Default: True.
  • max_box_fraction (float) – In terms of the size of the domain, the maximum length a light ray segment can be in order to span the redshift interval from one dataset to another. If using a zoom-in simulation, this parameter can be set to the length of the high resolution region so as to limit ray segments to that size. If the high resolution region is not cubical, the smallest side should be used. Default: 1.0 (the size of the box)
  • deltaz_min (float) – Specifies the minimum delta z between consecutive datasets in the returned list. Default: 0.0.
  • time_data (bool) – Whether or not to include time outputs when gathering datasets for time series. Default: True.
  • redshift_data (bool) – Whether or not to include redshift outputs when gathering datasets for time series. Default: True.

Examples

>>> co = CosmologySplice("enzo_tiny_cosmology/32Mpc_32.enzo", "Enzo")
>>> cosmo = co.create_cosmology_splice(1.0, 0.0)
plan_cosmology_splice(near_redshift, far_redshift, decimals=3, filename=None, start_index=0)[source]

Create imaginary list of redshift outputs to maximally span a redshift interval.

If you want to run a cosmological simulation that will have just enough data outputs to create a cosmology splice, this method will calculate a list of redshifts outputs that will minimally connect a redshift interval.

Parameters:
  • near_redshift (float) – The nearest (lowest) redshift in the cosmology splice list.
  • far_redshift (float) – The furthest (highest) redshift in the cosmology splice list.
  • decimals (int) – The decimal place to which the output redshift will be rounded. If the decimal place in question is nonzero, the redshift will be rounded up to ensure continuity of the splice. Default: 3.
  • filename (string) – If provided, a file will be written with the redshift outputs in the form in which they should be given in the enzo dataset. Default: None.
  • start_index (int) – The index of the first redshift output. Default: 0.

Examples

>>> from yt.analysis_modules.api import CosmologySplice
>>> my_splice = CosmologySplice('enzo_tiny_cosmology/32Mpc_32.enzo', 'Enzo')
>>> my_splice.plan_cosmology_splice(0.0, 0.1, filename='redshifts.out')