Random numbers
ocelot.util.random.points_on_sphere(shape, radians=True, phi_symmetric=True, seed=None)
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Draws random points on the surface of a unit sphere.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
shape
|
int
|
required number of deviates. Should be acceptable by np.random.rand(). |
required |
radians
|
bool
|
whether or not to return in radians. Default: True |
True
|
phi_symmetric
|
bool
|
whether or not to return a distribution for phi symmetric about zero (so, phi ~ [-pi/2, pi/2]) or whether to return one defined in the mathsy (but less useful for astronomy) way phi ~ [0, pi]. Default: True, i.e. phi is immediately usable as galactic latitude b or declination. |
True
|
seed
|
optional
|
Seed for the numpy random generator. Default: None |
None
|
Returns:
| Type | Description |
|---|---|
ndarray
|
theta values. |
ndarray
|
phi values. |
Notes
To draw random points on a sphere, you cannot simply use uniform deviates based on theta and phi! For a good explanation, see: http://mathworld.wolfram.com/SpherePointPicking.html
ocelot.util.random.unit_vectors(size, seed=None)
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Returns an array of random unit vectors on the surface of a 3D unit sphere.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
size
|
int
|
Number of unit vectors to return. |
required |
seed
|
optional
|
Seed for the numpy random generator. Default: None |
None
|
Returns:
| Type | Description |
|---|---|
ndarray
|
An array of shape (size, 3) of unit vectors. |
Notes
To draw random points on a sphere, you cannot simply use uniform deviates based on theta and phi! For a good explanation, see: http://mathworld.wolfram.com/SpherePointPicking.html
ocelot.util.random.fractal_noise_2d(resolution, seed=None)
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Creates 2d fractal (pink) noise.
Implemented for use in making synthetic (correlated) differential reddening.
This function is completely beyond me. Thanks, StackOverflow! https://stackoverflow.com/a/76605642
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
resolution
|
int
|
Resolution of the noise. |
required |
seed
|
optional
|
Seed for the numpy random generator. Default: None |
None
|
Returns:
| Type | Description |
|---|---|
ndarray
|
Array of shape (resolution, resolution) containing fractal noise. |