HeavisideAssembias¶
- class halotools.empirical_models.HeavisideAssembias(**kwargs)[source]¶
Bases:
object
Class used as an orthogonal mix-in to introduce step function-style assembly-biased behavior into any component model.
No positional arguments accepted; all argument are strictly keyword arguments.
- Parameters:
- method_name_to_decoratestring
Name of the method in the primary class whose behavior is being decorated
- lower_assembias_boundfloat
lower bound on the method being decorated with assembly bias
- upper_assembias_boundfloat
upper bound on the method being decorated with assembly bias
- sec_haloprop_keystring, optional
String giving the column name of the secondary halo property governing the assembly bias. Must be a key in the table passed to the methods of
HeavisideAssembiasComponent
. Default value is specified in themodel_defaults
module.- splitfloat or list, optional
Fraction or list of fractions between 0 and 1 defining how we split halos into two groupings based on their conditional secondary percentiles. Default is 0.5 for a constant 50/50 split.
- split_abscissalist, optional
Values of the primary halo property at which the halos are split as described above in the
split
argument. Ifloginterp
is set to True (the default behavior), the interpolation will be done in the logarithm of the primary halo property. Default is to assume a constant 50/50 split.- splitting_modelobject, optional
Model instance with a method called
splitting_method_name
used to split the input halos into two types.- splitting_method_namestring, optional
Name of method bound to
splitting_model
used to split the input halos into two types.- halo_type_tupletuple, optional
Tuple providing the information about how elements of the input
table
have been pre-divided into types. The first tuple entry must be a string giving the column name of the inputtable
that provides the halo-typing. The second entry gives the value that will be stored in this column for halos that are above the percentile split, the third entry gives the value for halos below the split.If provided, you must ensure that the splitting of the
table
was self-consistently performed with the inputsplit
, orsplit_abscissa
andsplit_ordinates
, orsplit_func
keyword arguments.- assembias_strengthfloat or list, optional
Fraction or sequence of fractions between -1 and 1 defining the assembly bias correlation strength. Default is 0.5.
- assembias_strength_abscissalist, optional
Values of the primary halo property at which the assembly bias strength is specified. Default is to assume a constant strength of 0.5. If passing a list, the strength will interpreted at the input
assembias_strength_abscissa
. Default is to assume a constant strength of 0.5.- loginterpbool, optional
If set to True, the interpolation will be done in the logarithm of the primary halo property, rather than linearly. Default is True.
Methods Summary
assembias_decorator
(func)Primary behavior of the
HeavisideAssembias
class.assembias_strength
(prim_haloprop)Method returns the strength of assembly bias as a function of the primary halo property.
percentile_splitting_function
(prim_haloprop)Method returns the fraction of halos that are
type-2
as a function of the input primary halo property.Methods Documentation
- assembias_decorator(func)[source]¶
Primary behavior of the
HeavisideAssembias
class.This method is used to introduce a boost/decrement of the baseline function in a manner that preserves the all-halo result. Any function with a semi-bounded range can be decorated with
assembias_decorator
. The baseline behavior can be anything whatsoever, such as mean star formation rate or mean halo occupation, provided it has a semi-bounded range.- Parameters:
- funcfunction object
Baseline function whose behavior is being decorated with assembly bias.
- Returns:
- wrapperfunction object
Decorated function that includes assembly bias effects.
- assembias_strength(prim_haloprop)[source]¶
Method returns the strength of assembly bias as a function of the primary halo property.
- Parameters:
- prim_haloproparray_like
Array storing the primary halo property.
- Returns:
- strengtharray_like
Strength of assembly bias as a function of the input halo property.
- percentile_splitting_function(prim_haloprop)[source]¶
Method returns the fraction of halos that are
type-2
as a function of the input primary halo property.- Parameters:
- prim_haloproparray_like
Array storing the primary halo property.
- Returns:
- splitfloat
Fraction of
type2
halos at the input primary halo property.