Ring2D

class astropy.modeling.functional_models.Ring2D(amplitude=1, x_0=0, y_0=0, r_in=1, width=1, r_out=None, **kwargs)

Bases: astropy.modeling.Fittable2DModel

Two dimensional radial symmetric Ring model.

Parameters:

amplitude : float

Value of the disk function

x_0 : float

x position center of the disk

y_0 : float

y position center of the disk

r_in : float

Inner radius of the ring

width : float

Width of the ring.

r_out : float

Outer Radius of the ring. Can be specified instead of width.

See also

Disk2D, TrapezoidDisk2D

Notes

Model formula:

\[\begin{split}f(r) = \left \{ \begin{array}{ll} A & : r_{in} \leq r \leq r_{out} \\ 0 & : \text{else} \end{array} \right.\end{split}\]

Where \(r_{out} = r_{in} + r_{width}\).

Attributes Summary

amplitude
input_units	This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).
param_names
r_in
width
x_0
y_0

Methods Summary

evaluate(x, y, amplitude, x_0, y_0, r_in, width)

Two dimensional Ring model function.

Attributes Documentation

amplitude = Parameter('amplitude', value=1.0)

input_units

This property is used to indicate what units or sets of units the evaluate method expects, and returns a dictionary mapping inputs to units (or None if any units are accepted).

Model sub-classes can also use function annotations in evaluate to indicate valid input units, in which case this property should not be overridden since it will return the input units based on the annotations.

param_names = ('amplitude', 'x_0', 'y_0', 'r_in', 'width')

r_in = Parameter('r_in', value=1.0)

width = Parameter('width', value=1.0)

x_0 = Parameter('x_0', value=0.0)

y_0 = Parameter('y_0', value=0.0)

Methods Documentation

static evaluate(x, y, amplitude, x_0, y_0, r_in, width)

Two dimensional Ring model function.