def test_hampel_scale():
np.random.seed(1000)
data = pd.Series(np.random.uniform(-1, 1, size=100))
data.iloc[20] = -25
data.iloc[40] = 15
data.iloc[60] = 5
assert not all(outliers.hampel(data) == outliers.hampel(data, scale=0.1))
def test_hampel_max_deviation():
"""Increasing max_deviation causes fewer values to be identified as
outliers."""
np.random.seed(1000)
data = pd.Series(np.random.uniform(-1, 1, size=100))
data.iloc[20] = -25
data.iloc[40] = 15
data.iloc[60] = 5
expected = pd.Series(False, index=data.index)
expected.iloc[[20, 40, 60]] = True
assert_series_equal(
data[outliers.hampel(data, window=11)],
data[expected]
)
expected.iloc[60] = False
assert_series_equal(
data[outliers.hampel(data, window=11, max_deviation=10)],
data[expected]
)
expected.iloc[40] = False
assert_series_equal(
data[outliers.hampel(data, window=11, max_deviation=12)],
data[expected]
)
def test_hampel_all_same():
"""outliers.hampel identifies no outlier if all data is the same."""
data = pd.Series(1, index=range(0, 50))
assert_series_equal(
outliers.hampel(data),
pd.Series(False, index=range(0, 50))
)
def test_hampel_one_outlier():
"""If all data is same but one value outliers.hampel should identify
that value as an outlier."""
np.random.seed(1000)
data = pd.Series(np.random.uniform(0, 1, size=50))
data.iloc[20] = 10
expected = pd.Series(False, index=data.index)
expected.iloc[20] = True
assert_series_equal(outliers.hampel(data, window=11), expected)
import pathlib
# %%
# First, we read in the ac_power_inv_7539_outliers example. Min-max normalized
# AC power is represented by the "value_normalized" column. There is a boolean
# column "outlier" where inserted outliers are labeled as True, and all other
# values are labeled as False. These outlier values were inserted manually into
# the data set to illustrate outlier detection by each of the functions.
# We use a normalized time series example provided by the PV Fleets Initiative.
# This example is adapted from the DuraMAT DataHub
# clipping data set:
# https://datahub.duramat.org/dataset/inverter-clipping-ml-training-set-real-data
pvanalytics_dir = pathlib.Path(pvanalytics.__file__).parent
ac_power_file_1 = pvanalytics_dir / 'data' / 'ac_power_inv_7539_outliers.csv'
data = pd.read_csv(ac_power_file_1, index_col=0, parse_dates=True)
print(data.head(10))
# %%
# We then use :py:func:`pvanalytics.quality.outliers.hampel` to identify
# outliers in the time series, and plot the data with the hampel outlier mask.
hampel_outlier_mask = hampel(data=data['value_normalized'],
window=10)
data['value_normalized'].plot()
data.loc[hampel_outlier_mask, 'value_normalized'].plot(ls='', marker='o')
plt.legend(labels=["AC Power", "Detected Outlier"])
plt.xlabel("Date")
plt.ylabel("Normalized AC Power")
plt.tight_layout()
plt.show()