circmoment¶

astropy.stats.
circmoment
(data, p=1.0, centered=False, axis=None, weights=None)[source]¶ Computes the
p
th trigonometric circular moment for an array of circular data. Parameters
 datanumpy.ndarray or Quantity
Array of circular (directional) data, which is assumed to be in radians whenever
data
isnumpy.ndarray
. pfloat, optional
Order of the circular moment.
 centeredBoolean, optional
If
True
, central circular moments are computed. Default value isFalse
. axisint, optional
Axis along which circular moments are computed. The default is to compute the circular moment of the flattened array.
 weightsnumpy.ndarray, optional
In case of grouped data, the ith element of
weights
represents a weighting factor for each group such thatsum(weights, axis)
equals the number of observations. See [1], remark 1.4, page 22, for detailed explanation.
 Returns
 circmomentnumpy.ndarray or Quantity
The first and second elements correspond to the direction and length of the
p
th circular moment, respectively.
References
 1
S. R. Jammalamadaka, A. SenGupta. “Topics in Circular Statistics”. Series on Multivariate Analysis, Vol. 5, 2001.
 2
C. Agostinelli, U. Lund. “Circular Statistics from ‘Topics in Circular Statistics (2001)’”. 2015. <https://cran.rproject.org/web/packages/CircStats/CircStats.pdf>
Examples
>>> import numpy as np >>> from astropy.stats import circmoment >>> from astropy import units as u >>> data = np.array([51, 67, 40, 109, 31, 358])*u.deg >>> circmoment(data, p=2) # doctest: +FLOAT_CMP (<Quantity 90.99263082432564 deg>, <Quantity 0.48004283892950717>)