The RV Model¶
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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)
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__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)
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__init__
(params, forward_model, time_base=0)[source]¶ Initialize self. See help(type(self)) for accurate signature.
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__weakref__
¶ list of weak references to the object (if defined)
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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
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mcmcscale
¶ step size to be used for MCMC fitting
Type: float
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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
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__init__
(value=None, vary=True, mcmcscale=None, linear=False)[source]¶ Initialize self. See help(type(self)) for accurate signature.
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__weakref__
¶ list of weak references to the object (if defined)
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-
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.
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basis
¶ Basis object
Type: radvel.Basis
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planet_parameters
¶ orbital parameters contained within the specified basis
Type: list
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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'})