SellmeierGlass¶

class gwcs.spectroscopy.SellmeierGlass(B_coef, C_coef, **kwargs)[source]¶

Bases: Model

Sellmeier equation for glass.

Parameters

B_coefndarray: Iterable of size 3 containing B coefficients.
C_coefndarray: Iterable of size 3 containing c coefficients in units of u.um**2.

Returns

nfloat: Refractive index.

Notes

Model formula:

\[n(\lambda)^2 = 1 + \frac{(B1 * \lambda^2 )}{(\lambda^2 - C1)} + \frac{(B2 * \lambda^2 )}{(\lambda^2 - C2)} + \frac{(B3 * \lambda^2 )}{(\lambda^2 - C3)}\]

References

1: https://en.wikipedia.org/wiki/Sellmeier_equation

Examples

>>> import astropy.units as u
>>> b_coef = [0.58339748, 0.46085267, 3.8915394]
>>> c_coef = [0.00252643, 0.010078333, 1200.556] * u.um**2
>>> model = SellmeierGlass(b_coef, c_coef)
>>> model(2 * u.m)
    <Quantity 2.43634758>

Attributes Summary

`B_coef`	B1, B2, B3 coefficients.
`C_coef`	C1, C2, C3 coefficients in units of um ** 2.
`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).
`linear`
`n_inputs`	The number of inputs.
`n_outputs`	The number of outputs.
`param_names`	Names of the parameters that describe models of this type.
`standard_broadcasting`

Methods Summary

`__call__`(*inputs[, model_set_axis, ...])	Evaluate this model using the given input(s) and the parameter values that were specified when the model was instantiated.
`evaluate`(wavelength, B_coef, C_coef)	Evaluate the model on some input variables.

Attributes Documentation

B_coef = Parameter('B_coef', value=[1. 1. 1.])¶: B1, B2, B3 coefficients.

C_coef = Parameter('C_coef', value=[0. 0. 0.])¶: C1, C2, C3 coefficients in units of um ** 2.

input_units¶

linear = False¶

n_inputs = 1¶: The number of inputs.

n_outputs = 1¶: The number of outputs.

param_names = ('B_coef', 'C_coef')¶

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.

standard_broadcasting = False¶

Methods Documentation

__call__(*inputs, model_set_axis=None, with_bounding_box=False, fill_value=nan, equivalencies=None, inputs_map=None, **new_inputs)¶: Evaluate this model using the given input(s) and the parameter values that were specified when the model was instantiated.

static evaluate(wavelength, B_coef, C_coef)[source]¶: Evaluate the model on some input variables.

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SellmeierGlass¶