waveformtools.BMS
The implementation of BMS transformations on the waveforms.
Functions
|
Boost the waveform given the unboosted waveform and the boost conformal factor. |
|
Compute the conformal factor for the boost transformation |
Compute the spherical Alpha supertranslation variable \(\alpha(\theta, \phi)\) given its modes. |
- waveformtools.BMS.boost_waveform(unboosted_waveform, conformal_factor)[source]
Boost the waveform given the unboosted waveform and the boost conformal factor.
- Parameters:
- non_boosted_waveform: list
A list with a single floating point number or a numpy array of the unboosted waveform. The waveform can have angular as well as time dimentions.
The nesting order should be that, given the list `non_boosted_waveform’, each item in the list refers to an array defined on the sphere at a particular time or frequency. The subitem will have dimensions [ntheta, nphi].
- conformal_factor: float/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.
- waveformtools.BMS.compute_conformal_k(vec_v, theta, phi, spin_phase=0)[source]
- Compute the conformal factor for the boost transformation
\(k = \exp(-2i \lambda) \gamma^3 (1 - \mathbf{v} \cdot \mathbf{r})^3\)
- Parameters:
- Returns:
- conformal_k: float
The conformal factor for the boost transformation as defined above.
- waveformtools.BMS.compute_supertransl_alpha(supertransl_alpha_modes, theta, phi)[source]
Compute the spherical Alpha supertranslation variable \(\alpha(\theta, \phi)\) given its modes. This method just multiplies the alpha modes with their corresponding spherical harmonic basis functions and returns the summed result.
- Parameters:
- Returns:
- supertransl_alpha_sphere: func
A function on the sphere (arguments \(\theta', math:\)phi’).