yt.analysis_modules.cosmological_observation.light_ray.light_ray.LightRay

class yt.analysis_modules.cosmological_observation.light_ray.light_ray.LightRay(parameter_filename, simulation_type=None, near_redshift=None, far_redshift=None, use_minimum_datasets=True, deltaz_min=0.0, minimum_coherent_box_fraction=0.0, time_data=True, redshift_data=True, find_outputs=False, load_kwargs=None)[source]
LightRay(parameter_filename, simulation_type=None,
near_redshift=None, far_redshift=None, use_minimum_datasets=True, deltaz_min=0.0, minimum_coherent_box_fraction=0.0, time_data=True, redshift_data=True, find_outputs=False, load_kwargs=None):

Create a LightRay object. A light ray is much like a light cone, in that it stacks together multiple datasets in order to extend a redshift interval. Unlike a light cone, which does randomly oriented projections for each dataset, a light ray consists of randomly oriented single rays. The purpose of these is to create synthetic QSO lines of sight.

Light rays can also be made from single datasets.

Once the LightRay object is set up, use LightRay.make_light_ray to begin making rays. Different randomizations can be created with a single object by providing different random seeds to make_light_ray.

Parameters:

parameter_filename : string

The path to the simulation parameter file or dataset.

simulation_type : optional, string

The simulation type. If None, the first argument is assumed to refer to a single dataset. Default: None

near_redshift : optional, float

The near (lowest) redshift for a light ray containing multiple datasets. Do not use is making a light ray from a single dataset. Default: None

far_redshift : optional, float

The far (highest) redshift for a light ray containing multiple datasets. Do not use is making a light ray from a single dataset. Default: None

use_minimum_datasets : optional, bool

If True, the minimum number of datasets is used to connect the initial and final redshift. If false, the light ray solution will contain as many entries as possible within the redshift interval. Default: True.

deltaz_min : optional, float

Specifies the minimum \Delta z between consecutive datasets in the returned list. Default: 0.0.

minimum_coherent_box_fraction : optional, float

Used with use_minimum_datasets set to False, this parameter specifies the fraction of the total box size to be traversed before rerandomizing the projection axis and center. This was invented to allow light rays with thin slices to sample coherent large scale structure, but in practice does not work so well. Try setting this parameter to 1 and see what happens. Default: 0.0.

time_data : optional, bool

Whether or not to include time outputs when gathering datasets for time series. Default: True.

redshift_data : optional, bool

Whether or not to include redshift outputs when gathering datasets for time series. Default: True.

find_outputs : optional, bool

Whether or not to search for datasets in the current directory. Default: False.

load_kwargs : optional, dict

Optional dictionary of kwargs to be passed to the “load” function, appropriate for use of certain frontends. E.g. Tipsy using “bounding_box” Gadget using “unit_base”, etc. Default : None

Methods