Fitting Model Sets

Fitting a polynomial model to multiple data sets simultaneously:

>>> from astropy.modeling import models, fitting
>>> import numpy as np
>>> p1 = models.Polynomial1D(3)
>>> p1.c0 = 1
>>> p1.c1 = 2
>>> print(p1)
Model: Polynomial1D
Inputs: ('x',)
Outputs: ('y',)
Model set size: 1
Degree: 3
Parameters:
     c0  c1  c2  c3
    --- --- --- ---
    1.0 2.0 0.0 0.0
>>> x = np.arange(10)
>>> y = p1(x)
>>> yy = np.array([y, y])
>>> p2 = models.Polynomial1D(3, n_models=2)
>>> pfit = fitting.LinearLSQFitter()
>>> new_model = pfit(p2, x, yy)
>>> print(new_model)  
Model: Polynomial1D
Inputs: 1
Outputs: 1
Model set size: 2
Degree: 3
Parameters:
     c0  c1         c2                 c3
    --- --- ------------------ -----------------
    1.0 2.0 -5.86673908219e-16 3.61636197841e-17
    1.0 2.0 -5.86673908219e-16 3.61636197841e-17