ConditionalDcorr

class hyppo.conditional.ConditionalDcorr(compute_distance='euclidean', use_cov=True, bandwidth=None, **kwargs)

Conditional Distance Covariance/Correlation (CDcov/CDcorr) test statistic and p-value.

CDcorr is a measure of dependence between two paired random matrices given a third random matrix of not necessarily equal dimensions 1. The coefficient is 0 if and only if the matrices are independent given third matrix.

Parameters
  • compute_distance (str, callable, or None, default: "euclidean") -- A function that computes the distance among the samples within each data matrix. Valid strings for compute_distance are, as defined in sklearn.metrics.pairwise_distances,

    • From scikit-learn: ["euclidean", "cityblock", "cosine", "l1", "l2", "manhattan"] See the documentation for scipy.spatial.distance for details on these metrics.

    • From scipy.spatial.distance: ["braycurtis", "canberra", "chebyshev", "correlation", "dice", "hamming", "jaccard", "kulsinski", "mahalanobis", "minkowski", "rogerstanimoto", "russellrao", "seuclidean", "sokalmichener", "sokalsneath", "sqeuclidean", "yule"] See the documentation for scipy.spatial.distance for details on these metrics.

    Set to None or "precomputed" if x and y are already distance matrices. To call a custom function, either create the distance matrix before-hand or create a function of the form metric(x, **kwargs) where x is the data matrix for which pairwise distances are calculated and **kwargs are extra arguements to send to your custom function.

  • use_cov (bool,) -- If True, then the statistic will compute the covariance rather than the correlation.

  • bandwith (str, scalar, 1d-array) -- The method used to calculate the bandwidth used for kernel density estimate of the conditional matrix. This can be ‘scott’, ‘silverman’, a scalar constant or a 1d-array with length r which is the dimensions of the conditional matrix. If None (default), ‘scott’ is used.

  • **kwargs -- Arbitrary keyword arguments for compute_distance.

References

1

Xueqin Wang, Wenliang Pan, Wenhao Hu, Yuan Tian, and Heping Zhang. Conditional distance correlation. Journal of the American Statistical Association, 110(512):1726–1734, 2015.

Methods Summary

ConditionalDcorr.statistic(x, y, z)

Helper function that calculates the CDcov/CDcorr test statistic.

ConditionalDcorr.test(x, y, z[, reps, ...])

Calculates the CDcov/CDcorr test statistic and p-value.


ConditionalDcorr.statistic(x, y, z)

Helper function that calculates the CDcov/CDcorr test statistic.

Parameters

x,y,z (ndarray of float) -- Input data matrices. x, y and z must have the same number of samples. That is, the shapes must be (n, p), (n, q) and (n, r) where n is the number of samples and p, q, and r are the number of dimensions. Alternatively, x and y can be distance matrices and z can be a similarity matrix where the shapes must be (n, n).

Returns

stat (float) -- The computed CDcov/CDcorr statistic.

ConditionalDcorr.test(x, y, z, reps=1000, workers=1, random_state=None)

Calculates the CDcov/CDcorr test statistic and p-value.

Parameters
  • x,y,z (ndarray of float) -- Input data matrices. x, y and z must have the same number of samples. That is, the shapes must be (n, p), (n, q) and (n, r) where n is the number of samples and p, q, and r are the number of dimensions. Alternatively, x and y can be distance matrices and z can be a similarity matrix where the shapes must be (n, n).

  • reps (int, default: 1000) -- The number of replications used to estimate the null distribution when using the permutation test used to calculate the p-value.

  • workers (int, default: 1) -- The number of cores to parallelize the p-value computation over. Supply -1 to use all cores available to the Process.

  • random_state (int, default: None) -- The random_state for permutation testing to be fixed for reproducibility.

Returns

  • stat (float) -- The computed CDcov/CDcorr statistic.

  • pvalue (float) -- The computed CDcov/CDcorr p-value.

Examples using hyppo.conditional.ConditionalDcorr