waveformtools.CoM
Centre of mass correction for the waveforms.
Functions
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Compute the nth order temporal moment of the COM coordinates. |
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Boost the waveform given the unboosted waveform and the boost conformal factor. |
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Computes the CoM correction alpha parameter: the mean displacement of the system, of the COM correction as defined in Woodford et al. 2019 (Phys. |
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Computes the CoM beta parameter: the mean drift of the system, of the COM correction as defined in Woodford et al. 2019 (Phys. |
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Compute the conformal factor for the boost transformation |
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Compute the translation scalar \(\alpha\) in its spherical harmonic components given the mean motion of the centre of mass. |
- waveformtools.CoM.X_com_moments(time_axis, Xcom, order)[source]
Compute the nth order temporal moment of the COM coordinates.
- Parameters:
- time_axis: 1d array
The time axis.
- Xcom: list
A list of three 1d arrays, each a 1d array containing the time series of the x, y and z co-ordinates in that order.
- order: int
The order of the moment.
- Returns:
- moments: list
A list containing three real numbers, one each for the moment of x, y and z locations.
- waveformtools.CoM.boost_waveform(unboosted_waveform, conformal_factor)[source]
Boost the waveform given the unboosted waveform and the boost conformal factor.
- Parameters:
- unboosted_waveform: spherical_array
A class instance of spherical array.
- conformal_factor: 2d array
The conformal factor for the Lorentz transformation. It may be a single floating point number or an array on a spherical grid. The array will be of dimensions [ntheta, nphi].
- gridinfo: class instance
The class instance that contains the properties of the spherical grid.
- Returns:
- boosted_waveform: sp_array
The class instance sp_array that contains the boosted waveform.
- waveformtools.CoM.compute_com_alpha(time_i, time_f, Xcom_0, Xcom_1)[source]
Computes the CoM correction alpha parameter: the mean displacement of the system, of the COM correction as defined in Woodford et al. 2019 (Phys. Rev. D 100, 124010).
- Parameters:
- time_i: float
initial time
- time_f: float
final time
- Xcom_0: list
A list containing the zeroth order moments of the COM.
- Xcom_1: list
A list containing the first order moments of the COM.
- Returns:
- com_alpha: list
The list containig the alpha parameter vector
- waveformtools.CoM.compute_com_beta(time_i, time_f, Xcom_0, Xcom_1)[source]
Computes the CoM beta parameter: the mean drift of the system, of the COM correction as defined in Woodford et al. 2019 (Phys. Rev. D 100, 124010).
- Parameters:
- time_i: float
initial time
- time_f: float
final time
- Xcom_0: list
A list containing the zeroth order moments of the COM.
- Xcom_1: list
A list containing the first order moments of the COM.
- Returns:
- com_beta: list
The list containig the alpha parameter vector
- waveformtools.CoM.compute_conformal_k(vec_v, info, spin_phase=0)[source]
- Compute the conformal factor for the boost transformation
:math:`k = exp(-2i lambda) gamma^3 (1 - mathbf{v} cdot mathbf{r})^3
- waveformtools.CoM.compute_translation_alpha_modes(time_axis, com_alpha, com_beta)[source]
Compute the translation scalar \(\alpha\) in its spherical harmonic components given the mean motion of the centre of mass. These are basically the quantities in Eq. (4-5d) in the reference Woodford et al. 2019.
- Parameters:
- time_axis: 1d array
The 1D array containing the time axis of the simulation.
- alpha: 1d array
The 1D array containing the mean co-ordinate displacement of the COM of the system.
- beta: 1d array
The 1D array containing the mean co-ordinate velocity of the COM.
- Returns:
- alpha_modesmodes_array
A waveforms.modes_array object containing the SH decomposition of the ‘Alpha’ supertranslation variable.