新的Scipy v0.11提供了一个用于光谱分析的软件包。遗憾的是，文档很少，并且可用的示例不多。
作为一个婴儿的例子，我正在尝试发现一个正弦波。不幸的是，它会预测1而不是预期的2pi。有什么想法吗？
# imports the numerical array and scientific computing packages
import numpy as np
import scipy as sp
from scipy.signal import spectral
# generates 100 evenly spaced points between 1 and 1000
time = np.linspace(1, 1000, 100)
# computes the sine value of each of those points
mags = np.sin(time)
# scales the sine values so that the mean is 0 and the variance is 1 (the documentation specifies that this must be done)
scaled_mags = (mags-mags.mean())/mags.std()
# generates 1000 frequencies between 0.01 and 1
freqs = np.linspace(0.01, 1, 1000)
# computes the Lomb Scargle Periodogram of the time and scaled magnitudes using each frequency as a guess
periodogram = spectral.lombscargle(time, scaled_mags, freqs)
# returns the inverse of the frequence (i.e. the period) of the largest periodogram value
1/freqs[np.argmax(periodogram)]
这会返回1而不是2pi ~= 1/0.6366的预期时段。有什么想法吗？
答案 0 :(得分：7)
请注意spectral.lombscargle的最后一个参数是根据docstring的角频率：
Parameters
----------
x : array_like
Sample times.
y : array_like
Measurement values.
freqs : array_like
Angular frequencies for output periodogram.