utils.py 文件源码

def _scipy_bivariate_kde(x, y, bw, gridsize, cut, clip):
    """Compute a bivariate kde using scipy."""
    data = np.c_[x, y]
    kde = stats.gaussian_kde(data.T)
    data_std = data.std(axis=0, ddof=1)
    if isinstance(bw, string_types):
        bw = "scotts" if bw == "scott" else bw
        bw_x = getattr(kde, "%s_factor" % bw)() * data_std[0]
        bw_y = getattr(kde, "%s_factor" % bw)() * data_std[1]
    elif np.isscalar(bw):
        bw_x, bw_y = bw, bw
    else:
        msg = ("Cannot specify a different bandwidth for each dimension "
               "with the scipy backend. You should install statsmodels.")
        raise ValueError(msg)
    x_support = _kde_support(data[:, 0], bw_x, gridsize, cut, clip[0])
    y_support = _kde_support(data[:, 1], bw_y, gridsize, cut, clip[1])
    xx, yy = np.meshgrid(x_support, y_support)
    z = kde([xx.ravel(), yy.ravel()]).reshape(xx.shape)
    return xx, yy, z