The RV Model

class radvel.model.GeneralRVModel(params, forward_model, time_base=0)[source]

A generalized Model

Parameters
  • params (radvel.Parameters) – The parameters upon which the RV model depends.

  • forward_model (callable) –

    The function that defines the signal as a function of time and parameters. The forward model is called as

    forward_model(time, params, *args, **kwargs) -> float

  • time_base (float) – time relative to which ‘dvdt’ and ‘curv’ terms are computed.

Examples

>>> import radvel
#  In this example, we'll assume a function called 'my_rv_function' that
#  computes RV values has been defined elsewhere. We'll assume that
#  'my_rv_function' depends on planets' usual RV parameters
#  contained in radvel.Parameters as well as some additional
#  parameter, 'my_param'.
>>> params = radvel.Parameters(2)
>>> params['my_param'] = rv.Parameter(my_param_value,vary=True)
>>> rvmodel = radvel.GeneralRVModel(myparams,my_rv_function)
>>> rv = rvmodel(10)
__call__(t, *args, **kwargs)[source]

Compute the signal

Parameters

t (array of floats) – Timestamps to calculate the model

Returns

model at each time in t

Return type

vel (array of floats)

__init__(params, forward_model, time_base=0)[source]
__weakref__

list of weak references to the object (if defined)

class radvel.model.Parameter(value=None, vary=True, mcmcscale=None, linear=False)[source]

Object to store attributes of each orbital parameter .. attribute:: value

value of parameter.

type

float

vary

True if parameter is allowed to vary in MCMC or max likelihood fits, false if fixed

Type

Bool

mcmcscale

step size to be used for MCMC fitting

Type

float

linear

if vary=False and linear=True for gamma parameters then they will be calculated analytically using the trick. derived by Timothy Brandt.

Type

bool

__init__(value=None, vary=True, mcmcscale=None, linear=False)[source]
__repr__()[source]

Return repr(self).

__weakref__

list of weak references to the object (if defined)

class radvel.model.Parameters(num_planets, basis='per tc secosw sesinw logk', planet_letters=None)[source]

Object to store the model parameters.

Parameters to describe a radial velocity orbit stored as an OrderedDict.

Parameters
  • num_planets (int) – Number of planets in model

  • basis (string) – parameterization of orbital parameters. See radvel.basis.Basis for a list of valid basis strings.

  • planet_letters (dict [optional) – custom map to match the planet numbers in the Parameter object to planet letters. Default {1: ‘b’, 2: ‘c’, etc.}. The keys of this dictionary must all be integers.

basis

Basis object

Type

radvel.Basis

planet_parameters

orbital parameters contained within the specified basis

Type

list

num_planets

number of planets in the model

Type

int

Examples

>>> import radvel
# create a Parameters object for a 2-planet system with
# custom planet number to letter mapping
>>> params = radvel.Parameters(2, planet_letters={1:'d', 2:'e'})
__init__(num_planets, basis='per tc secosw sesinw logk', planet_letters=None)[source]
__reduce__()[source]

Return state information for pickling

tex_labels(param_list=None)[source]

Map Parameters keys to pretty TeX code representations.

Parameters

param_list (list [optional]) – Manually pass a list of parameter labels

Returns

dictionary mapping Parameters keys to TeX code

Return type

dict

class radvel.model.RVModel(params, time_base=0)[source]

Generic RV Model

This class defines the methods common to all RV modeling classes. The different RV models, with different parameterizations, all inherit from this class.

__init__(params, time_base=0)[source]