# statsmodels.tsa.stattools.ccf¶

statsmodels.tsa.stattools.ccf(x, y, unbiased=True)[source]

cross-correlation function for 1d

Parameters
x, yarrays

time series data

unbiasedboolean

if True, then denominators for autocovariance is n-k, otherwise n

Returns
ccfarray

cross-correlation function of x and y

Notes

This is based np.correlate which does full convolution. For very long time series it is recommended to use fft convolution instead.

If unbiased is true, the denominator for the autocovariance is adjusted but the autocorrelation is not an unbiased estimtor.