# Linear1D¶

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

One dimensional Line model.

Parameters
slopefloat

Slope of the straight line

interceptfloat

Intercept of the straight line

Other Parameters
fixeda dict, 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.

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 slope

Methods Summary

 evaluate(x, slope, intercept) One dimensional Line model function fit_deriv(x, slope, intercept) 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')
slope = Parameter('slope', value=1.0)

Methods Documentation

static evaluate(x, slope, intercept)[source]

One dimensional Line model function

static fit_deriv(x, slope, intercept)[source]

One dimensional Line model derivative with respect to parameters