Shift

class astropy.modeling.functional_models.Shift(offset=0, **kwargs)

Bases: Fittable1DModel

Shift a coordinate.

Parameters:

offsetfloat

Offset to add to a coordinate.

Attributes Summary

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
offset
param_names	Names of the parameters that describe models of this type.

Methods Summary

evaluate(x, offset)	One dimensional Shift model function.
fit_deriv(x, *params)	One dimensional Shift model derivative with respect to parameter.
sum_of_implicit_terms(x)	Evaluate the implicit term (x) of one dimensional Shift model.

Attributes Documentation

input_units

linear = True

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

param_names = ('offset',)

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.

Methods Documentation

static evaluate(x, offset)

One dimensional Shift model function.

static fit_deriv(x, *params)

One dimensional Shift model derivative with respect to parameter.

static sum_of_implicit_terms(x)

Evaluate the implicit term (x) of one dimensional Shift model.