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linedance-app/venv/lib/python3.12/site-packages/sklearn/utils/_mask.py

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+# Authors: The scikit-learn developers
+# SPDX-License-Identifier: BSD-3-Clause
+
+from contextlib import suppress
+
+import numpy as np
+from scipy import sparse as sp
+
+from sklearn.utils._missing import is_scalar_nan
+from sklearn.utils._param_validation import validate_params
+from sklearn.utils.fixes import _object_dtype_isnan
+
+
+def _get_dense_mask(X, value_to_mask):
+    with suppress(ImportError, AttributeError):
+        # We also suppress `AttributeError` because older versions of pandas do
+        # not have `NA`.
+        import pandas
+
+        if value_to_mask is pandas.NA:
+            return pandas.isna(X)
+
+    if is_scalar_nan(value_to_mask):
+        if X.dtype.kind == "f":
+            Xt = np.isnan(X)
+        elif X.dtype.kind in ("i", "u"):
+            # can't have NaNs in integer array.
+            Xt = np.zeros(X.shape, dtype=bool)
+        else:
+            # np.isnan does not work on object dtypes.
+            Xt = _object_dtype_isnan(X)
+    else:
+        Xt = X == value_to_mask
+
+    return Xt
+
+
+def _get_mask(X, value_to_mask):
+    """Compute the boolean mask X == value_to_mask.
+
+    Parameters
+    ----------
+    X : {ndarray, sparse matrix} of shape (n_samples, n_features)
+        Input data, where ``n_samples`` is the number of samples and
+        ``n_features`` is the number of features.
+
+    value_to_mask : {int, float}
+        The value which is to be masked in X.
+
+    Returns
+    -------
+    X_mask : {ndarray, sparse matrix} of shape (n_samples, n_features)
+        Missing mask.
+    """
+    if not sp.issparse(X):
+        # For all cases apart of a sparse input where we need to reconstruct
+        # a sparse output
+        return _get_dense_mask(X, value_to_mask)
+
+    Xt = _get_dense_mask(X.data, value_to_mask)
+
+    sparse_constructor = sp.csr_matrix if X.format == "csr" else sp.csc_matrix
+    Xt_sparse = sparse_constructor(
+        (Xt, X.indices.copy(), X.indptr.copy()), shape=X.shape, dtype=bool
+    )
+
+    return Xt_sparse
+
+
+@validate_params(
+    {
+        "X": ["array-like", "sparse matrix"],
+        "mask": ["array-like"],
+    },
+    prefer_skip_nested_validation=True,
+)
+def safe_mask(X, mask):
+    """Return a mask which is safe to use on X.
+
+    Parameters
+    ----------
+    X : {array-like, sparse matrix}
+        Data on which to apply mask.
+
+    mask : array-like
+        Mask to be used on X.
+
+    Returns
+    -------
+    mask : ndarray
+        Array that is safe to use on X.
+
+    Examples
+    --------
+    >>> from sklearn.utils import safe_mask
+    >>> from scipy.sparse import csr_matrix
+    >>> data = csr_matrix([[1], [2], [3], [4], [5]])
+    >>> condition = [False, True, True, False, True]
+    >>> mask = safe_mask(data, condition)
+    >>> data[mask].toarray()
+    array([[2],
+           [3],
+           [5]])
+    """
+    mask = np.asarray(mask)
+    if np.issubdtype(mask.dtype, np.signedinteger):
+        return mask
+
+    if hasattr(X, "toarray"):
+        ind = np.arange(mask.shape[0])
+        mask = ind[mask]
+    return mask
+
+
+def axis0_safe_slice(X, mask, len_mask):
+    """Return a mask which is safer to use on X than safe_mask.
+
+    This mask is safer than safe_mask since it returns an
+    empty array, when a sparse matrix is sliced with a boolean mask
+    with all False, instead of raising an unhelpful error in older
+    versions of SciPy.
+
+    See: https://github.com/scipy/scipy/issues/5361
+
+    Also note that we can avoid doing the dot product by checking if
+    the len_mask is not zero in _huber_loss_and_gradient but this
+    is not going to be the bottleneck, since the number of outliers
+    and non_outliers are typically non-zero and it makes the code
+    tougher to follow.
+
+    Parameters
+    ----------
+    X : {array-like, sparse matrix}
+        Data on which to apply mask.
+
+    mask : ndarray
+        Mask to be used on X.
+
+    len_mask : int
+        The length of the mask.
+
+    Returns
+    -------
+    mask : ndarray
+        Array that is safe to use on X.
+    """
+    if len_mask != 0:
+        return X[safe_mask(X, mask), :]
+    return np.zeros(shape=(0, X.shape[1]))
+
+
+def indices_to_mask(indices, mask_length):
+    """Convert list of indices to boolean mask.
+
+    Parameters
+    ----------
+    indices : list-like
+        List of integers treated as indices.
+    mask_length : int
+        Length of boolean mask to be generated.
+        This parameter must be greater than max(indices).
+
+    Returns
+    -------
+    mask : 1d boolean nd-array
+        Boolean array that is True where indices are present, else False.
+
+    Examples
+    --------
+    >>> from sklearn.utils._mask import indices_to_mask
+    >>> indices = [1, 2 , 3, 4]
+    >>> indices_to_mask(indices, 5)
+    array([False,  True,  True,  True,  True])
+    """
+    if mask_length <= np.max(indices):
+        raise ValueError("mask_length must be greater than max(indices)")
+
+    mask = np.zeros(mask_length, dtype=bool)
+    mask[indices] = True
+
+    return mask