import spectrum
from spectrum.datasets import marple_data
import scipy.signal
import pylab

# Define AR filter coefficients and some data accordingly
a = [1, -2.2137, 2.9403, -2.1697, 0.9606];
x = scipy.signal.lfilter([1], a, pylab.randn(1,256))

# study different order
order = pylab.arange(1, 25)
rho = [spectrum.aryule(x[0], i, norm='biased')[1] for i in order]
pylab.plot(order, spectrum.AIC(len(x[0]), rho, order), label='AIC')