pint.models.noise_model.PLRedNoise

class pint.models.noise_model.PLRedNoise[source]

Bases: CorrelatedNoiseComponent

Timing noise with a power-law spectrum.

Over the long term, pulsars are observed to experience timing noise dominated by low frequencies. This can occur, for example, if the torque on the pulsar varies randomly. If the torque experiences white noise, the phase we observe will experience “red” noise, that is noise dominated by the lowest frequency. This results in errors that are correlated between TOAs over fairly long time spans.

Parameters supported:

Name / Aliases	Description	Kind
RNAMP	Amplitude of powerlaw red noise.	number
RNIDX	Spectral index of powerlaw red noise.	number
TNREDAMP	Amplitude of powerlaw red noise in tempo2 format	number
TNREDGAM	Spectral index of powerlaw red noise in tempo2 format	number
TNREDC	Number of red noise frequencies.	integer
TNREDFLOG	Number of logarithmically spaced red noise frequencies in the basis.	integer
TNREDFLOG_FACTOR	Scaling factor for the log-spaced frequencies (2 -> [1/8,1/4,1/2,…])	number
TNREDTSPAN	Time span corresponding to the fundamental frequency of the achromatic red noise Fourier series (data span is used by default).	yr

References

Lentati et al. 2014, MNRAS 437(3), 3004-3023 [1]
van Haasteren & Vallisneri, 2014, MNRAS 446(2), 1170-1174 [2]

Methods

`add_param`(param[, deriv_func, setup])	Add a parameter to the Component.
`get_dm_noise_basis`(toas)	The DM part of the basis matrix for wideband datasets.
`get_noise_basis`(toas)	Return a Fourier design matrix for red noise.
`get_noise_weights`(toas)	Return power law red noise weights.
`get_params_of_type`(param_type)	Get all the parameters in timing model for one specific Parameter subtype.
`get_plc_vals`()	Retrieve power-law parameters and frequency-basis parameters from the model, substituting defaults if unspecified.
`get_prefix_mapping_component`(prefix)	Get the index mapping for the prefix parameters.
`get_time_frequencies`(toas)	Return the frequencies of the noise model
`get_wideband_noise_basis`(toas)	The wideband noise basis including both TOA and DM parts.
`is_in_parfile`(para_dict)	Check if this subclass included in parfile.
`match_param_aliases`(alias)	Return the parameter corresponding to this alias.
`param_help`()	Print help lines for all available parameters in model.
`pl_rn_basis_weight_pair`(toas)	Return a Fourier design matrix and power law red noise weights.
`pl_rn_cov_matrix`(toas)
`print_par`([format])	param format: Parfile output format. PINT outputs the 'tempo', 'tempo2' and 'pint'
`register_deriv_funcs`(func, param)	Register the derivative function in to the deriv_func dictionaries.
`remove_param`(param)	Remove a parameter from the Component.
`set_special_params`(spcl_params)
`setup`()	Finalize construction loaded values.
`validate`()	Validate loaded values.
`validate_toas`(toas)	Check that this model component has TOAs where needed.

Attributes

`aliases_map`	Return all the aliases and map to the PINT parameter name.
`category`
`component_types`
`free_params_component`	Return the free parameters in the component.
`introduces_correlated_errors`
`introduces_dm_errors`
`is_time_correlated`
`param_prefixs`
`register`

get_plc_vals() → Tuple[float, float, int, int, float][source]: Retrieve power-law parameters and frequency-basis parameters from the model, substituting defaults if unspecified.

get_time_frequencies(toas: TOAs) → ndarray[source]: Return the frequencies of the noise model

get_noise_basis(toas: TOAs) → ndarray[source]

Return a Fourier design matrix for red noise.

See the documentation for pl_rn_basis_weight_pair function for details.

get_noise_weights(toas: TOAs) → ndarray[source]

Return power law red noise weights.

See the documentation for pl_rn_basis_weight_pair for details.

pl_rn_basis_weight_pair(toas: TOAs) → Tuple[ndarray, ndarray][source]

Return a Fourier design matrix and power law red noise weights.

A Fourier design matrix contains the sine and cosine basis_functions in a Fourier series expansion. The weights used are the power-law PSD values at frequencies n/T, where n is in [1, TNREDC] and T is the total observing duration of the dataset.

add_param(param: Parameter, deriv_func: Callable | None = None, setup: bool = False)

Add a parameter to the Component.

The parameter is stored in an attribute on the Component object. Its name is also recorded in a list, self.params.

Parameters:

param (pint.models.Parameter) – The parameter to be added.
deriv_func (function) – Derivative function for parameter.

property aliases_map: Dict[str, str]

Return all the aliases and map to the PINT parameter name.

This property returns a dictionary from the current in timing model parameters’ aliase to the pint defined parameter names. For the aliases of a prefixed parameter, the aliase with an existing prefix index maps to the PINT defined parameter name with the same index. Behind the scenes, the indexed parameter adds the indexed aliase to its aliase list.

property free_params_component: List[str]

Return the free parameters in the component.

This function collects the non-frozen parameters.

Return type:: A list of free parameters.

get_dm_noise_basis(toas): The DM part of the basis matrix for wideband datasets. This is non-zero only for DM noise. The output is a numpy array but it has units of dmu/s by convention since the noise amplitudes are defined to have dimensions of time.

get_params_of_type(param_type: str) → List[str]: Get all the parameters in timing model for one specific Parameter subtype.

get_prefix_mapping_component(prefix: str) → Dict[int, str]

Get the index mapping for the prefix parameters.

Parameters:: prefix (str) – Name of prefix.
Returns:: A dictionary with prefix parameter real index as key and parameter name as value.
Return type:: dict

get_wideband_noise_basis(toas): The wideband noise basis including both TOA and DM parts. The TOA part of the matrix is dimensionless but the DM part of the basis has units of dmu/s.

is_in_parfile(para_dict: Dict) → bool

Check if this subclass included in parfile.

Parameters:: para_dict (dictionary) – A dictionary contain all the parameters with values in string from one parfile
Returns:: Whether the subclass is included in the parfile.
Return type:: bool

match_param_aliases(alias: str) → str

Return the parameter corresponding to this alias.

Parameters:: alias (str) – Alias name.

Note

This function only searches the parameter aliases within the current component. If one wants to search the aliases in the scope of TimingModel, please use TimingModel.match_param_aliase().

param_help() → str: Print help lines for all available parameters in model.

print_par(format: Literal['tempo', 'tempo2', 'pint'] = 'pint') → str

Parameters:: format (str, optional) – Parfile output format. PINT outputs the ‘tempo’, ‘tempo2’ and ‘pint’ format. The defaul format is pint. Actual formatting done elsewhere.
Returns:: str
Return type:: formatted line for par file

register_deriv_funcs(func: Callable, param: str) → None

Register the derivative function in to the deriv_func dictionaries.

Parameters:

func (callable) – Calculates the derivative
param (str) – Name of parameter the derivative is with respect to

remove_param(param: str | Parameter) → None

Remove a parameter from the Component.

Parameters:: param (str or pint.models.Parameter) – The parameter to remove.

setup() → None: Finalize construction loaded values.

validate() → None: Validate loaded values.

validate_toas(toas) → None: Check that this model component has TOAs where needed.