kerr module

This module contains the basic class for calculating time-like geodesics in Kerr Space-Time:

class einsteinpy.metric.kerr.Kerr(pos_vec, vel_vec, time, M, a)

Class for defining Kerr Goemetry Methdos

classmethod from_BL(pos_vec, vel_vec, time, M, a)

Constructor Initialize from Boyer-Lindquist Coordinates

Parameters

  • pos_vec (list) – list of r, theta & phi components along with ~astropy.units

  • vel_vec (list) – list of velocities of r, theta & phi components along with ~astropy.units

  • time (s) – Time of start

  • M (kg) – Mass of the body

  • a (float) – Spin factor of massive body

classmethod from_cartesian(pos_vec, vel_vec, time, M, a)

Constructor Initialize from Cartesian Coordinates

Parameters

  • pos_vec (list) – list of x, y and z components along with ~astropy.units

  • vel_vec (list) – list of velocities of x, y, and z components along with ~astropy.units

  • time (s) – Time of start

  • M (kg) – Mass of the body

  • a (float) – Spin factor of massive body

calculate_trajectory(start_lambda=0.0, end_lambda=10.0, stop_on_singularity=True, OdeMethodKwargs={'stepsize': 0.001}, return_cartesian=False)

Calculate trajectory in manifold according to geodesic equation

Parameters

  • start_lambda (float) – Starting lambda, defaults to 0.0, (lambda ~= t)

  • end_lamdba (float) – Lambda where iteartions will stop, defaults to 100000

  • stop_on_singularity (bool) – Whether to stop further computation on reaching singularity, defaults to True

  • OdeMethodKwargs (dict) – Kwargs to be supplied to the ODESolver, defaults to {‘stepsize’: 1e-3} Dictionary with key ‘stepsize’ along with an float value is expected.

  • return_cartesian (bool) – True if coordinates and velocities are required in cartesian coordinates(SI units), defaults to False

Returns

(~numpy.array of lambda, (n,8) shape ~numpy.array of [t, pos1, pos2, pos3, velocity_of_time, vel1, vel2, vel3])

Return type

tuple

calculate_trajectory_iterator(start_lambda=0.0, stop_on_singularity=True, OdeMethodKwargs={'stepsize': 0.001}, return_cartesian=False)

Calculate trajectory in manifold according to geodesic equation Yields an iterator

Parameters

  • start_lambda (float) – Starting lambda, defaults to 0.0, (lambda ~= t)

  • stop_on_singularity (bool) – Whether to stop further computation on reaching singularity, defaults to True

  • OdeMethodKwargs (dict) – Kwargs to be supplied to the ODESolver, defaults to {‘stepsize’: 1e-3} Dictionary with key ‘stepsize’ along with an float value is expected.

  • return_cartesian (bool) – True if coordinates and velocities are required in cartesian coordinates(SI units), defaults to Falsed

Yields

tuple – (lambda, (8,) shape ~numpy.array of [t, pos1, pos2, pos3, velocity_of_time, vel1, vel2, vel3])