pyriemann.preprocessing.Whitening¶
- class pyriemann.preprocessing.Whitening(metric='euclid', dim_red=None, verbose=False)¶
Whitening, and optional unsupervised dimension reduction.
Implementation of the whitening, and an optional unsupervised dimension reduction, with SPD matrices as inputs.
- Parameters:
- metricstr, default=”euclid”
Metric for the estimation of mean matrix used for whitening and dimension reduction. For the list of supported metrics, see
pyriemann.utils.mean.mean_covariance()
.- dim_redNone | dict, default=None
- If
None
: no dimension reduction during whitening.
- If
{'n_components': val}
: dimension reduction defining the number of components;
val
must be an integer superior to 1.- If
{'expl_var': val}
: dimension reduction selecting the number of components such that the amount of variance that needs to be explained is greater than the percentage specified by
val
.val
must be a float in (0,1], typically0.99
.- If
{'max_cond': val}
: dimension reduction selecting the number of components such that the condition number of the mean matrix is lower than
val
. This threshold has a physiological interpretation, because it can be viewed as the ratio between the power of the strongest component (usually, eye-blink source) and the power of the lowest component you don’t want to keep (acquisition sensor noise).val
must be a float strictly superior to 1, typically 100.
- If
- verbosebool, default=False
Verbose flag.
- Attributes:
- n_components_int
If fit, the number of components after dimension reduction.
- filters_ndarray, shape
(n_channels, n_components_)
If fit, the spatial filters to whiten SPD matrices.
- inv_filters_ndarray, shape
(n_components_, n_channels)
If fit, the spatial filters to unwhiten SPD matrices.
Notes
Added in version 0.2.7.
- __init__(metric='euclid', dim_red=None, verbose=False)¶
Init.
- fit(X, y=None, sample_weight=None)¶
Train whitening spatial filters.
- Parameters:
- Xndarray, shape (n_matrices, n_channels, n_channels)
Set of SPD matrices.
- yNone
Ignored as unsupervised.
- sample_weightNone | ndarray, shape (n_matrices,), default=None
Weight of each matrix, to compute the weighted mean matrix used for whitening and dimension reduction. If None, it uses equal weights.
- Returns:
- selfWhitening instance
The Whitening instance.
- fit_transform(X, y=None, sample_weight=None)¶
Fit and transform in a single function.
- Parameters:
- Xndarray, shape (n_matrices, n_channels, n_channels)
Set of SPD matrices.
- yNone
Ignored as unsupervised.
- sample_weightNone | ndarray, shape (n_matrices,), default=None
Weight of each matrix, to compute the weighted mean matrix used for whitening and dimension reduction. If None, it uses equal weights.
- Returns:
- X_newndarray, shape (n_matrices, n_components, n_components)
Set of whitened, and optionally reduced, SPD matrices.
- get_metadata_routing()¶
Get metadata routing of this object.
Please check User Guide on how the routing mechanism works.
- Returns:
- routingMetadataRequest
A
MetadataRequest
encapsulating routing information.
- get_params(deep=True)¶
Get parameters for this estimator.
- Parameters:
- deepbool, default=True
If True, will return the parameters for this estimator and contained subobjects that are estimators.
- Returns:
- paramsdict
Parameter names mapped to their values.
- inverse_transform(X)¶
Apply inverse whitening spatial filters.
- Parameters:
- Xndarray, shape (n_matrices, n_components, n_components)
Set of whitened, and optionally reduced, SPD matrices.
- Returns:
- X_newndarray, shape (n_matrices, n_channels, n_channels)
Set of unwhitened, and optionally unreduced, SPD matrices.
- partial_fit(X, y=None, *, sample_weight=None, alpha=None)¶
Partially fit whitening spatial filters.
- Parameters:
- Xndarray, shape (n_matrices, n_channels, n_channels)
Set of SPD matrices.
- yNone
Ignored as unsupervised.
- sample_weightNone | ndarray, shape (n_matrices,), default=None
Weights for each matrix. If None, it uses equal weights.
- alphafloat | None, default=None
Update rate in [0, 1] for the mean: 0 for no update, 1 for full update. If None,
alpha
is defined asn_matrices
divided by the number of matrices that have been already used for fit.
- Returns:
- selfWhitening instance
The Whitening instance.
Notes
Added in version 0.7.
- set_fit_request(*, sample_weight: bool | None | str = '$UNCHANGED$') Whitening ¶
Request metadata passed to the
fit
method.Note that this method is only relevant if
enable_metadata_routing=True
(seesklearn.set_config()
). Please see User Guide on how the routing mechanism works.The options for each parameter are:
True
: metadata is requested, and passed tofit
if provided. The request is ignored if metadata is not provided.False
: metadata is not requested and the meta-estimator will not pass it tofit
.None
: metadata is not requested, and the meta-estimator will raise an error if the user provides it.str
: metadata should be passed to the meta-estimator with this given alias instead of the original name.
The default (
sklearn.utils.metadata_routing.UNCHANGED
) retains the existing request. This allows you to change the request for some parameters and not others.Added in version 1.3.
Note
This method is only relevant if this estimator is used as a sub-estimator of a meta-estimator, e.g. used inside a
Pipeline
. Otherwise it has no effect.- Parameters:
- sample_weightstr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED
Metadata routing for
sample_weight
parameter infit
.
- Returns:
- selfobject
The updated object.
- set_output(*, transform=None)¶
Set output container.
See Introducing the set_output API for an example on how to use the API.
- Parameters:
- transform{“default”, “pandas”, “polars”}, default=None
Configure output of transform and fit_transform.
“default”: Default output format of a transformer
“pandas”: DataFrame output
“polars”: Polars output
None: Transform configuration is unchanged
Added in version 1.4: “polars” option was added.
- Returns:
- selfestimator instance
Estimator instance.
- set_params(**params)¶
Set the parameters of this estimator.
The method works on simple estimators as well as on nested objects (such as
Pipeline
). The latter have parameters of the form<component>__<parameter>
so that it’s possible to update each component of a nested object.- Parameters:
- **paramsdict
Estimator parameters.
- Returns:
- selfestimator instance
Estimator instance.
- set_partial_fit_request(*, alpha: bool | None | str = '$UNCHANGED$', sample_weight: bool | None | str = '$UNCHANGED$') Whitening ¶
Request metadata passed to the
partial_fit
method.Note that this method is only relevant if
enable_metadata_routing=True
(seesklearn.set_config()
). Please see User Guide on how the routing mechanism works.The options for each parameter are:
True
: metadata is requested, and passed topartial_fit
if provided. The request is ignored if metadata is not provided.False
: metadata is not requested and the meta-estimator will not pass it topartial_fit
.None
: metadata is not requested, and the meta-estimator will raise an error if the user provides it.str
: metadata should be passed to the meta-estimator with this given alias instead of the original name.
The default (
sklearn.utils.metadata_routing.UNCHANGED
) retains the existing request. This allows you to change the request for some parameters and not others.Added in version 1.3.
Note
This method is only relevant if this estimator is used as a sub-estimator of a meta-estimator, e.g. used inside a
Pipeline
. Otherwise it has no effect.- Parameters:
- alphastr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED
Metadata routing for
alpha
parameter inpartial_fit
.- sample_weightstr, True, False, or None, default=sklearn.utils.metadata_routing.UNCHANGED
Metadata routing for
sample_weight
parameter inpartial_fit
.
- Returns:
- selfobject
The updated object.
- transform(X)¶
Apply whitening spatial filters.
- Parameters:
- Xndarray, shape (n_matrices, n_channels, n_channels)
Set of SPD matrices.
- Returns:
- X_newndarray, shape (n_matrices, n_components, n_components)
Set of whitened, and optionally reduced, SPD matrices.