Exemplo n.º 1
0
def test_robust_scaler_zero_variance_features():
    """Check RobustScaler on toy data with zero variance features"""
    X = [[0., 1., +0.5],
         [0., 1., -0.1],
         [0., 1., +1.1]]

    scaler = RobustScaler()
    X_trans = scaler.fit_transform(X)

    # NOTE: for such a small sample size, what we expect in the third column
    # depends HEAVILY on the method used to calculate quantiles. The values
    # here were calculated to fit the quantiles produces by np.percentile
    # using numpy 1.9 Calculating quantiles with
    # scipy.stats.mstats.scoreatquantile or scipy.stats.mstats.mquantiles
    # would yield very different results!
    X_expected = [[0., 0., +0.0],
                  [0., 0., -1.0],
                  [0., 0., +1.0]]
    assert_array_almost_equal(X_trans, X_expected)
    X_trans_inv = scaler.inverse_transform(X_trans)
    assert_array_almost_equal(X, X_trans_inv)

    # make sure new data gets transformed correctly
    X_new = [[+0., 2., 0.5],
             [-1., 1., 0.0],
             [+0., 1., 1.5]]
    X_trans_new = scaler.transform(X_new)
    X_expected_new = [[+0., 1., +0.],
                      [-1., 0., -0.83333],
                      [+0., 0., +1.66667]]
    assert_array_almost_equal(X_trans_new, X_expected_new, decimal=3)
Exemplo n.º 2
0
def test_robust_scaler_iris():
    X = iris.data
    scaler = RobustScaler()
    X_trans = scaler.fit_transform(X)
    assert_array_almost_equal(np.median(X_trans, axis=0), 0)
    X_trans_inv = scaler.inverse_transform(X_trans)
    assert_array_almost_equal(X, X_trans_inv)
    q = np.percentile(X_trans, q=(25, 75), axis=0)
    iqr = q[1] - q[0]
    assert_array_almost_equal(iqr, 1)
Exemplo n.º 3
0
def test_robust_scaler_iris():
    X = iris.data
    scaler = RobustScaler()
    X_trans = scaler.fit_transform(X)
    assert_array_almost_equal(np.median(X_trans, axis=0), 0)
    X_trans_inv = scaler.inverse_transform(X_trans)
    assert_array_almost_equal(X, X_trans_inv)
    q = np.percentile(X_trans, q=(25, 75), axis=0)
    iqr = q[1] - q[0]
    assert_array_almost_equal(iqr, 1)
Exemplo n.º 4
0
def test_robust_scaler_zero_variance_features():
    """Check RobustScaler on toy data with zero variance features"""
    X = [[0., 1., +0.5], [0., 1., -0.1], [0., 1., +1.1]]

    scaler = RobustScaler()
    X_trans = scaler.fit_transform(X)

    # NOTE: for such a small sample size, what we expect in the third column
    # depends HEAVILY on the method used to calculate quantiles. The values
    # here were calculated to fit the quantiles produces by np.percentile
    # using numpy 1.9 Calculating quantiles with
    # scipy.stats.mstats.scoreatquantile or scipy.stats.mstats.mquantiles
    # would yield very different results!
    X_expected = [[0., 0., +0.0], [0., 0., -1.0], [0., 0., +1.0]]
    assert_array_almost_equal(X_trans, X_expected)
    X_trans_inv = scaler.inverse_transform(X_trans)
    assert_array_almost_equal(X, X_trans_inv)

    # make sure new data gets transformed correctly
    X_new = [[+0., 2., 0.5], [-1., 1., 0.0], [+0., 1., 1.5]]
    X_trans_new = scaler.transform(X_new)
    X_expected_new = [[+0., 1., +0.], [-1., 0., -0.83333], [+0., 0., +1.66667]]
    assert_array_almost_equal(X_trans_new, X_expected_new, decimal=3)