velocity module

This module contains the basic classes for time differentials of coordinate systems and the transformations:

class einsteinpy.coordinates.velocity.CartesianDifferential(x, y, z, v_x, v_y, v_z)

Class for calculating and transforming the velocity in Cartesian coordinates.

Constructor.

Parameters

• x (Quantity) –

• y (Quantity) –

• z (Quantity) –

• v_x (Quantity) –

• v_y (Quantity) –

• v_z (Quantity) –

si_values()

Function for returning values in SI units.

Returns

Array containing values in SI units (m, m, m, m/s, m/s, m/s)

Return type

ndarray

velocities(return_np=False)

Function for returning velocity.

Parameters

return_np (bool) – True for numpy array with SI values, False for list with astropy units. Defaults to False

Returns

Array or list containing velocity.

Return type

ndarray or list

spherical_differential()

Function to convert velocity to spherical coordinates velocity

Returns

Spherical representation of the velocity in Cartesian Coordinates.

Return type

SphericalDifferential

bl_differential(a)

Function to convert velocity to Boyer-Lindquist coordinates

Parameters

a (Quantity) – a = J/Mc , the angular momentum per unit mass of the black hole per speed of light.

Returns

Boyer-Lindquist representation of the velocity in Cartesian Coordinates.

Return type

BoyerLindquistDifferential

class einsteinpy.coordinates.velocity.SphericalDifferential(r, theta, phi, v_r, v_t, v_p)

Class for calculating and transforming the velocity in Spherical coordinates.

Constructor.

Parameters

• r (Quantity) –

• theta (Quantity) –

• phi (Quantity) –

• v_r (Quantity) –

• v_t (Quantity) –

• v_p (Quantity) –

si_values()

Function for returning values in SI units.

Returns

Array containing values in SI units (m, rad, rad, m/s, rad/s, rad/s)

Return type

ndarray

velocities(return_np=False)

Function for returning velocity.

Parameters

return_np (bool) – True for numpy array with SI values, False for list with astropy units. Defaults to False

Returns

Array or list containing velocity.

Return type

ndarray or list

cartesian_differential()

Function to convert velocity to cartesian coordinates

Returns

Cartesian representation of the velocity in Spherical Coordinates.

Return type

CartesianDifferential

bl_differential(a)

Function to convert velocity to Boyer-Lindquist coordinates

Parameters

a (Quantity) – a = J/Mc , the angular momentum per unit mass of the black hole per speed of light.

Returns

Boyer-Lindquist representation of the velocity in Spherical Coordinates.

Return type

BoyerLindquistDifferential

class einsteinpy.coordinates.velocity.BoyerLindquistDifferential(r, theta, phi, v_r, v_t, v_p, a)

Class for calculating and transforming the velocity in Boyer-Lindquist coordinates

Constructor.

Parameters

• r (Quantity) –

• theta (Quantity) –

• phi (Quantity) –

• v_r (Quantity) –

• v_t (Quantity) –

• v_p (Quantity) –

• a (Quantity) –

si_values()

Function for returning values in SI units.

Returns

Array containing values in SI units (m, rad, rad, m/s, rad/s, rad/s)

Return type

ndarray

velocities(return_np=False)

Function for returning velocity.

Parameters

return_np (bool) – True for numpy array with SI values, False for list with astropy units. Defaults to False

Returns

Array or list containing velocity.

Return type

ndarray or list

cartesian_differential()

Function to convert velocity to cartesian coordinates

Returns

Cartesian representation of the velocity in Boyer-Lindquist Coordinates.

Return type

CartesianDifferential

spherical_differential()

Function to convert velocity to spherical coordinates

Returns

Spherical representation of the velocity in Boyer-Lindquist Coordinates.

Return type

SphericalDifferential