Eigenframe (ligo.skymap.coordinates.eigenframe)

Astropy coordinate frame for eigendecomposition of a cloud of points or a 3D sky map.

class ligo.skymap.coordinates.eigenframe.EigenFrame(*args, copy=True, representation_type=None, differential_type=None, **kwargs)[source] [edit on github]

Bases: astropy.coordinates.BaseCoordinateFrame

A coordinate frame that has its axes aligned with the principal components of a cloud of points.

classmethod for_coords(coords)[source] [edit on github]

Create a coordinate frame that has its axes aligned with the principal components of a cloud of points.

Parameters
coordsastropy.coordinates.SkyCoord

A cloud of points

Returns
frameEigenFrame

A new coordinate frame

classmethod for_skymap(prob, distmu, distsigma, nest=False)[source] [edit on github]

Create a coordinate frame that has its axes aligned with the principal components of a 3D sky map.

Parameters
probnumpy.ndarray

Marginal probability (pix^-2)

distmunumpy.ndarray

Distance location parameter (Mpc)

distsigmanumpy.ndarray

Distance scale parameter (Mpc)

distnormnumpy.ndarray

Distance normalization factor (Mpc^-2)

nestbool, default=False

Indicates whether the input sky map is in nested rather than ring-indexed HEALPix coordinates (default: ring).

Returns
frameEigenFrame

A new coordinate frame