test_extras.py 文件源码

def test_2d_w_missing(self):
        # Test cov on 2D variable w/ missing value
        x = self.data
        x[-1] = masked
        x = x.reshape(3, 4)
        valid = np.logical_not(getmaskarray(x)).astype(int)
        frac = np.dot(valid, valid.T)
        xf = (x - x.mean(1)[:, None]).filled(0)
        assert_almost_equal(cov(x),
                            np.cov(xf) * (x.shape[1] - 1) / (frac - 1.))
        assert_almost_equal(cov(x, bias=True),
                            np.cov(xf, bias=True) * x.shape[1] / frac)
        frac = np.dot(valid.T, valid)
        xf = (x - x.mean(0)).filled(0)
        assert_almost_equal(cov(x, rowvar=False),
                            (np.cov(xf, rowvar=False) *
                             (x.shape[0] - 1) / (frac - 1.)))
        assert_almost_equal(cov(x, rowvar=False, bias=True),
                            (np.cov(xf, rowvar=False, bias=True) *
                             x.shape[0] / frac))