def fit(self, X):
"""Fit detector.
Parameters
----------
X : dataframe of shape (n_samples, n_features)
The input samples.
"""
# validate inputs X and y (optional)
X = X.to_numpy()
X = check_array(X)
# PCA is recommended to use on the standardized data (zero mean and
# unit variance).
if self.standardization:
X, self.scaler_ = standardizer(X, keep_scalar=True)
self.detector_ = sklearn_PCA(n_components=self.n_components,
copy=self.copy,
whiten=self.whiten,
svd_solver=self.svd_solver,
tol=self.tol,
iterated_power=self.iterated_power,
random_state=self.random_state)
self.detector_.fit(X=X, y=None)
# copy the attributes from the sklearn PCA object
self.n_components_ = self.detector_.n_components_
self.components_ = self.detector_.components_
# validate the number of components to be used for outlier detection
if self.n_selected_components is None:
self.n_selected_components_ = self.n_components_
else:
self.n_selected_components_ = self.n_selected_components
check_parameter(self.n_selected_components_, 1, self.n_components_,
include_left=True, include_right=True,
param_name='n_selected_components_')
# use eigenvalues as the weights of eigenvectors
self.w_components_ = np.ones([self.n_components_, ])
if self.weighted:
self.w_components_ = self.detector_.explained_variance_ratio_
# outlier scores is the sum of the weighted distances between each
# sample to the eigenvectors. The eigenvectors with smaller
# eigenvalues have more influence
# Not all eigenvectors are used, only n_selected_components_ smallest
# are used since they better reflect the variance change
self.selected_components_ = self.components_[
-1 * self.n_selected_components_:, :]
self.selected_w_components_ = self.w_components_[
-1 * self.n_selected_components_:]
self.decision_scores_ = np.sum(
cdist(X, self.selected_components_) / self.selected_w_components_,
axis=1).ravel()
self._process_decision_scores()
return self
def test_function():
check_parameter(2, low=1, high=3)
standardizer(np.random.rand(3, 2) * 100)
str2bool('True')
def function_test():
check_parameter(2)
standardizer(np.random.rand(3,2)*100)
str2bool('True')