circcorrcoef¶
- astropy.stats.circcorrcoef(alpha, beta, axis=None, weights_alpha=None, weights_beta=None)[source]¶
Computes the circular correlation coefficient between two array of circular data.
- Parameters:
- alpha
ndarray
orQuantity
Array of circular (directional) data, which is assumed to be in radians whenever
data
isnumpy.ndarray
.- beta
ndarray
orQuantity
Array of circular (directional) data, which is assumed to be in radians whenever
data
isnumpy.ndarray
.- axis
int
, optional Axis along which circular correlation coefficients are computed. The default is the compute the circular correlation coefficient of the flattened array.
- weights_alpha
numpy.ndarray
, optional In case of grouped data, the i-th element of
weights_alpha
represents a weighting factor for each group such thatsum(weights_alpha, axis)
equals the number of observations. See [1], remark 1.4, page 22, for detailed explanation.- weights_beta
numpy.ndarray
, optional See description of
weights_alpha
.
- alpha
- Returns:
- rho
ndarray
orQuantity
[:ref: ‘dimensionless’] Circular correlation coefficient.
- rho
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.r-project.org/web/packages/CircStats/CircStats.pdf>
Examples
>>> import numpy as np >>> from astropy.stats import circcorrcoef >>> from astropy import units as u >>> alpha = np.array([356, 97, 211, 232, 343, 292, 157, 302, 335, 302, ... 324, 85, 324, 340, 157, 238, 254, 146, 232, 122, ... 329])*u.deg >>> beta = np.array([119, 162, 221, 259, 270, 29, 97, 292, 40, 313, 94, ... 45, 47, 108, 221, 270, 119, 248, 270, 45, 23])*u.deg >>> circcorrcoef(alpha, beta) <Quantity 0.2704648826748831>