Refactor

datasets/flwr_datasets/partitioner/distribution_partitioner.py

@@ -14,7 +14,7 @@
 # ==============================================================================
 
 """ Distribution partitioner."""
-from typing import Dict, List, Optional, Union
+from typing import Dict, List, Optional
 
 import numpy as np
 from flwr_datasets.partitioner.partitioner import Partitioner
@@ -68,13 +68,17 @@ class label distribution. `float` values are rounded to the nearest `int`.
     >>> # Generate a vector from a log-normal probability distribution
     >>> rng = np.random.default_rng(2024)
     >>> mu, sigma = 0., 2.
-    >>> distribution_proba = rng.lognormal(mu, sigma, (num_clients*num_unique_labels_per_client,))
+    >>> distribution_proba = rng.lognormal(
+    >>>    mu,
+    >>>    sigma,
+    >>>    (num_clients*num_unique_labels_per_client),
+    >>> )
     >>>
     >>> partitioner = DistributionPartitioner(
     >>>     distribution_array=distribution_proba,
     >>>     num_partitions=num_clients,
     >>>     num_unique_labels_per_partition=num_labels_per_client,
-    >>>     partition_by="label",  # Assumes that the dataset has a target column `label`
+    >>>     partition_by="label",  # Dataset has a target column `label`
     >>>     preassigned_num_samples_per_label=5,
     >>> )
     >>> fds = FederatedDataset(dataset="mnist", partitioners={"train": partitioner})
@@ -155,40 +159,45 @@ def _determine_partition_id_to_indices_if_needed(
                 unique_label_to_indices[unique_label]
             )
 
-        label_distribution = np.fromiter(label_distribution_dict.values(), dtype=float)
+        if self._rescale:
+            # Compute the normalized distribution for each class label
+            self._distribution_array = self._distribution_array / np.sum(
+                self._distribution_array, axis=-1, keepdims=True
+            )
 
-        # Compute the normalized distribution for each class label
-        self._distribution_array = self._distribution_array / np.sum(
-            self._distribution_array, axis=-1, keepdims=True
-        )
+            # Compute the total preassigned number of samples per label for all labels
+            # and partitions. This sum will be subtracted
+            # from the label distribution from the original dataset, and added back later.
+            # It ensures that (1) each partition will have at least
+            # `self._preassigned_num_samples_per_label` and (2) there is sufficient
+            # indices to sample from the dataset.
+            total_preassigned_samples = int(
+                self._preassigned_num_samples_per_label
+                * self._num_unique_labels_per_partition
+                * self._num_partitions
+                / self._num_unique_labels
+            )
 
-        # Compute the total preassigned number of samples per label for all labels
-        # and partitions. This sum will be subtracted
-        # from the label distribution from the original dataset, and added back later.
-        # It ensures that (1) each partition will have at least
-        # `self._preassigned_num_samples_per_label` and (2) there is sufficient
-        # indices to sample from the dataset.
-        total_preassigned_samples = int(
-            self._preassigned_num_samples_per_label
-            * self._num_unique_labels_per_partition
-            * self._num_partitions
-            / self._num_unique_labels
-        )
+            label_distribution = np.fromiter(
+                label_distribution_dict.values(),
+                dtype=float,
+            )
 
-        # Subtract the preassigned total amount from the label distribution,
-        # we'll add these back later.
-        label_distribution -= total_preassigned_samples
+            # Subtract the preassigned total amount from the label distribution,
+            # we'll add these back later.
+            label_distribution -= total_preassigned_samples
 
-        # Rescale normalized distribution with the actual label distribution.
-        # Each row represents the number of samples to be taken for that class label
-        # and the sum of each row equals the total of each class label.
-        # TODO: Skip this step if rescale = False
-        label_sampling_matrix = np.floor(
-            (self._distribution_array * label_distribution[:, np.newaxis])
-        ).astype(int)
+            # Rescale normalized distribution with the actual label distribution.
+            # Each row represents the number of samples to be taken for that class label
+            # and the sum of each row equals the total of each class label.
+            label_sampling_matrix = np.floor(
+                (self._distribution_array * label_distribution[:, np.newaxis])
+            ).astype(int)
 
-        # Add back the preassigned total amount
-        label_sampling_matrix += self._preassigned_num_samples_per_label
+            # Add back the preassigned total amount
+            label_sampling_matrix += self._preassigned_num_samples_per_label
+        else:
+            label_sampling_matrix = self._distribution_array.astype(int)
 
         # Create the label sampling dictionary
         label_samples = {