Videre

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

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+"""Utilities for random sampling."""
+
+# Authors: The scikit-learn developers
+# SPDX-License-Identifier: BSD-3-Clause
+
+import array
+
+import numpy as np
+import scipy.sparse as sp
+
+from sklearn.utils import check_random_state
+from sklearn.utils._random import sample_without_replacement
+
+__all__ = ["sample_without_replacement"]
+
+
+def _random_choice_csc(n_samples, classes, class_probability=None, random_state=None):
+    """Generate a sparse random matrix given column class distributions
+
+    Parameters
+    ----------
+    n_samples : int,
+        Number of samples to draw in each column.
+
+    classes : list of size n_outputs of arrays of size (n_classes,)
+        List of classes for each column.
+
+    class_probability : list of size n_outputs of arrays of \
+        shape (n_classes,), default=None
+        Class distribution of each column. If None, uniform distribution is
+        assumed.
+
+    random_state : int, RandomState instance or None, default=None
+        Controls the randomness of the sampled classes.
+        See :term:`Glossary <random_state>`.
+
+    Returns
+    -------
+    random_matrix : sparse csc matrix of size (n_samples, n_outputs)
+
+    """
+    data = array.array("i")
+    indices = array.array("i")
+    indptr = array.array("i", [0])
+
+    for j in range(len(classes)):
+        classes[j] = np.asarray(classes[j])
+        if classes[j].dtype.kind != "i":
+            raise ValueError("class dtype %s is not supported" % classes[j].dtype)
+        classes[j] = classes[j].astype(np.int64, copy=False)
+
+        # use uniform distribution if no class_probability is given
+        if class_probability is None:
+            class_prob_j = np.empty(shape=classes[j].shape[0])
+            class_prob_j.fill(1 / classes[j].shape[0])
+        else:
+            class_prob_j = np.asarray(class_probability[j])
+
+        if not np.isclose(np.sum(class_prob_j), 1.0):
+            raise ValueError(
+                "Probability array at index {0} does not sum to one".format(j)
+            )
+
+        if class_prob_j.shape[0] != classes[j].shape[0]:
+            raise ValueError(
+                "classes[{0}] (length {1}) and "
+                "class_probability[{0}] (length {2}) have "
+                "different length.".format(
+                    j, classes[j].shape[0], class_prob_j.shape[0]
+                )
+            )
+
+        # If 0 is not present in the classes insert it with a probability 0.0
+        if 0 not in classes[j]:
+            classes[j] = np.insert(classes[j], 0, 0)
+            class_prob_j = np.insert(class_prob_j, 0, 0.0)
+
+        # If there are nonzero classes choose randomly using class_probability
+        rng = check_random_state(random_state)
+        if classes[j].shape[0] > 1:
+            index_class_0 = np.flatnonzero(classes[j] == 0).item()
+            p_nonzero = 1 - class_prob_j[index_class_0]
+            nnz = int(n_samples * p_nonzero)
+            ind_sample = sample_without_replacement(
+                n_population=n_samples, n_samples=nnz, random_state=random_state
+            )
+            indices.extend(ind_sample)
+
+            # Normalize probabilities for the nonzero elements
+            classes_j_nonzero = classes[j] != 0
+            class_probability_nz = class_prob_j[classes_j_nonzero]
+            class_probability_nz_norm = class_probability_nz / np.sum(
+                class_probability_nz
+            )
+            classes_ind = np.searchsorted(
+                class_probability_nz_norm.cumsum(), rng.uniform(size=nnz)
+            )
+            data.extend(classes[j][classes_j_nonzero][classes_ind])
+        indptr.append(len(indices))
+
+    return sp.csc_matrix((data, indices, indptr), (n_samples, len(classes)), dtype=int)