Ring2D¶

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

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

widthfloat

Width of the ring.

r_outfloat

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 Names of the parameters that describe models of this type. 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
param_names = ('amplitude', 'x_0', 'y_0', 'r_in', 'width')

Names of the parameters that describe models of this type.

The parameters in this tuple are in the same order they should be passed in when initializing a model of a specific type. Some types of models, such as polynomial models, have a different number of parameters depending on some other property of the model, such as the degree.

When defining a custom model class the value of this attribute is automatically set by the Parameter attributes defined in the class body.

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.