Ring2D

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

Bases: astropy.modeling.Fittable2DModel

Two dimensional radial symmetric Ring model.

Parameters
amplitudefloat

Value of the disk function

x_0float

x position center of the disk

y_0float

y position center of the disk

r_infloat

Inner radius of the ring

widthfloat

Width of the ring.

r_outfloat

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

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)[source]

Two dimensional Ring model function.