`python`中的加权高斯核密度估计 [英] Weighted Gaussian kernel density estimation in `python`

问题描述

更新:scipy.stats.gaussian_kde 现在支持加权样本.请参阅

实施细节

加权算术平均值为

.

Update: Weighted samples are now supported by scipy.stats.gaussian_kde. See here and here for details.

It is currently not possible to use scipy.stats.gaussian_kde to estimate the density of a random variable based on weighted samples. What methods are available to estimate densities of continuous random variables based on weighted samples?

解决方案

Neither sklearn.neighbors.KernelDensity nor statsmodels.nonparametric seem to support weighted samples. I modified scipy.stats.gaussian_kde to allow for heterogeneous sampling weights and thought the results might be useful for others. An example is shown below.

An ipython notebook can be found here: http://nbviewer.ipython.org/gist/tillahoffmann/f844bce2ec264c1c8cb5

Implementation details

The weighted arithmetic mean is

The unbiased data covariance matrix is then given by

The bandwidth can be chosen by scott or silverman rules as in scipy. However, the number of samples used to calculate the bandwidth is Kish's approximation for the effective sample size.

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