Linear1D

class astropy.modeling.functional_models.Linear1D(slope=1, intercept=0, **kwargs)

Bases: Fittable1DModel

One dimensional Line model.

Parameters:

slopefloat

Slope of the straight line

interceptfloat

Intercept of the straight line

Other Parameters:

fixeddict, optional

A dictionary {parameter_name: boolean} of parameters to not be varied during fitting. True means the parameter is held fixed. Alternatively the fixed property of a parameter may be used.

tieddict, optional

A dictionary {parameter_name: callable} of parameters which are linked to some other parameter. The dictionary values are callables providing the linking relationship. Alternatively the tied property of a parameter may be used.

boundsdict, optional

A dictionary {parameter_name: value} of lower and upper bounds of parameters. Keys are parameter names. Values are a list or a tuple of length 2 giving the desired range for the parameter. Alternatively, the min and max properties of a parameter may be used.

eqconslist, optional

A list of functions of length n such that eqcons[j](x0,*args) == 0.0 in a successfully optimized problem.

ineqconslist, optional

A list of functions of length n such that ieqcons[j](x0,*args) >= 0.0 is a successfully optimized problem.

See also

Const1D

Notes

Model formula:

\[f(x) = a x + b\]

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).
intercept
linear
param_names	Names of the parameters that describe models of this type.
slope

Methods Summary

evaluate(x, slope, intercept)	One dimensional Line model function.
fit_deriv(x, *params)	One dimensional Line model derivative with respect to parameters.

Attributes Documentation

input_units

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

linear = True

param_names = ('slope', 'intercept')

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.

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

Methods Documentation

static evaluate(x, slope, intercept)

One dimensional Line model function.

static fit_deriv(x, *params)

One dimensional Line model derivative with respect to parameters.