# LinearLSQFitter¶

class astropy.modeling.fitting.LinearLSQFitter[source]

Bases: object

A class performing a linear least square fitting.

Uses numpy.linalg.lstsq to do the fitting. Given a model and data, fits the model to the data and changes the model’s parameters. Keeps a dictionary of auxiliary fitting information.

Notes

Note that currently LinearLSQFitter does not support compound models.

Attributes Summary

Methods Summary

 __call__(model, x, y[, z, weights, rcond]) Fit data to this model.

Attributes Documentation

supported_constraints = ['fixed']
supports_masked_input = True

Methods Documentation

__call__(model, x, y, z=None, weights=None, rcond=None)[source]

Fit data to this model.

Parameters
modelFittableModel

model to fit to x, y, z

xarray

Input coordinates

yarray_like

Input coordinates

zarray_like, optional

Input coordinates. If the dependent (y or z) co-ordinate values are provided as a numpy.ma.MaskedArray, any masked points are ignored when fitting. Note that model set fitting is significantly slower when there are masked points (not just an empty mask), as the matrix equation has to be solved for each model separately when their co-ordinate grids differ.

weightsarray, optional

Weights for fitting. For data with Gaussian uncertainties, the weights should be 1/sigma.

rcondfloat, optional

Cut-off ratio for small singular values of a. Singular values are set to zero if they are smaller than rcond times the largest singular value of a.

equivalencieslist or None, optional and keyword-only argument

List of additional equivalencies that are should be applied in case x, y and/or z have units. Default is None.

Returns
model_copyFittableModel

a copy of the input model with parameters set by the fitter