def manifold_radii()

in evaluations/evaluator.py [0:0]

• 25 lines of code
• 5 McCabe index (conditional complexity)

    def manifold_radii(self, features: np.ndarray) -> np.ndarray:
        num_images = len(features)

        # Estimate manifold of features by calculating distances to k-NN of each sample.
        radii = np.zeros([num_images, self.num_nhoods], dtype=np.float32)
        distance_batch = np.zeros([self.row_batch_size, num_images], dtype=np.float32)
        seq = np.arange(max(self.nhood_sizes) + 1, dtype=np.int32)

        for begin1 in range(0, num_images, self.row_batch_size):
            end1 = min(begin1 + self.row_batch_size, num_images)
            row_batch = features[begin1:end1]

            for begin2 in range(0, num_images, self.col_batch_size):
                end2 = min(begin2 + self.col_batch_size, num_images)
                col_batch = features[begin2:end2]

                # Compute distances between batches.
                distance_batch[
                    0 : end1 - begin1, begin2:end2
                ] = self.distance_block.pairwise_distances(row_batch, col_batch)

            # Find the k-nearest neighbor from the current batch.
            radii[begin1:end1, :] = np.concatenate(
                [
                    x[:, self.nhood_sizes]
                    for x in _numpy_partition(distance_batch[0 : end1 - begin1, :], seq, axis=1)
                ],
                axis=0,
            )

        if self.clamp_to_percentile is not None:
            max_distances = np.percentile(radii, self.clamp_to_percentile, axis=0)
            radii[radii > max_distances] = 0
        return radii