Merge pull request #622 from nextcloud/hdbscan

lib/Clustering/DualTreeBall.php

@@ -0,0 +1,137 @@
+<?php
+/*
+ * Copyright (c) 2023 The Recognize contributors.
+ * This file is licensed under the Affero General Public License version 3 or later. See the COPYING file.
+ */
+
+namespace OCA\Recognize\Clustering;
+
+use Rubix\ML\Datasets\Labeled;
+use Rubix\ML\Graph\Nodes\Ball;
+use Rubix\ML\Helpers\Stats;
+use Rubix\ML\Kernels\Distance\Distance;
+use function Rubix\ML\argmax;
+
+class DualTreeBall extends Ball {
+	protected float $longestDistanceInNode = INF;
+	protected bool $fullyConnected = false;
+	protected $setId;
+
+
+	public function setLongestDistance($longestDistance): void {
+		if ($longestDistance < $this->longestDistanceInNode) {
+			$this->longestDistanceInNode = $longestDistance;
+		}
+	}
+
+	public function getLongestDistance(): float {
+		return $this->longestDistanceInNode;
+	}
+
+	public function resetLongestEdge(): void {
+		$this->longestDistanceInNode = INF;
+		foreach ($this->children() as $child) {
+			$child->resetLongestEdge();
+		}
+	}
+
+	public function resetFullyConnectedStatus(): void {
+		$this->fullyConnected = false;
+		foreach ($this->children() as $child) {
+			$child->resetFullyConnectedStatus();
+		}
+	}
+
+	/**
+	 * @return null|int|string
+	 */
+	public function getSetId() {
+		if (!$this->fullyConnected) {
+			return null;
+		}
+		return $this->setId;
+	}
+
+	public function isFullyConnected(): bool {
+		return $this->fullyConnected;
+	}
+
+	/**
+	 * @param array $labelToSetId
+	 * @return null|int|string
+	 */
+	public function propagateSetChanges(array &$labelToSetId) {
+		if ($this->fullyConnected) {
+			// If we are already fully connected, we just need to check if the
+			// set id has changed
+			foreach ($this->children() as $child) {
+				$this->setId = $child->propagateSetChanges($labelToSetId);
+			}
+
+			return $this->setId;
+		}
+
+		// If, and only if, both children are fully connected and in the same set id then
+		// we, too, are fully connected
+		$setId = null;
+		foreach ($this->children() as $child) {
+			$retVal = $child->propagateSetChanges($labelToSetId);
+
+			if ($retVal === null) {
+				return null;
+			}
+
+			if ($setId !== null && $setId !== $retVal) {
+				return null;
+			}
+
+			$setId = $retVal;
+		}
+
+		$this->setId = $setId;
+		$this->fullyConnected = true;
+
+		return $this->setId;
+	}
+
+	/**
+	 * Factory method to build a hypersphere by splitting the dataset into left and right clusters.
+	 *
+	 * @param \Rubix\ML\Datasets\Labeled $dataset
+	 * @param \Rubix\ML\Kernels\Distance\Distance $kernel
+	 * @return self
+	 */
+	public static function split(Labeled $dataset, Distance $kernel): self {
+		$center = [];
+
+		foreach ($dataset->features() as $column => $values) {
+			if ($dataset->featureType($column)->isContinuous()) {
+				$center[] = Stats::mean($values);
+			} else {
+				$center[] = argmax(array_count_values($values));
+			}
+		}
+
+		$distances = [];
+
+		foreach ($dataset->samples() as $sample) {
+			$distances[] = $kernel->compute($sample, $center);
+		}
+
+		$radius = max($distances) ?: 0.0;
+
+		$leftCentroid = $dataset->sample(argmax($distances));
+
+		$distances = [];
+
+		foreach ($dataset->samples() as $sample) {
+			$distances[] = $kernel->compute($sample, $leftCentroid);
+		}
+
+		$rightCentroid = $dataset->sample(argmax($distances));
+
+		$subsets = $dataset->spatialSplit($leftCentroid, $rightCentroid, $kernel);
+
+		return new self($center, $radius, $subsets);
+	}
+}

lib/Clustering/DualTreeClique.php

@@ -0,0 +1,106 @@
+<?php
+/*
+ * Copyright (c) 2023 The Recognize contributors.
+ * This file is licensed under the Affero General Public License version 3 or later. See the COPYING file.
+ */
+
+namespace OCA\Recognize\Clustering;
+
+use Rubix\ML\Datasets\Labeled;
+use Rubix\ML\Graph\Nodes\Clique;
+use Rubix\ML\Helpers\Stats;
+use Rubix\ML\Kernels\Distance\Distance;
+use function Rubix\ML\argmax;
+
+class DualTreeClique extends Clique {
+	protected float $longestDistanceInNode = INF;
+	protected bool $fullyConnected = false;
+	/**
+	 * @var null|int|string
+	 */
+	protected $setId;
+
+	public function setLongestDistance(float $longestDistance): void {
+		$this->longestDistanceInNode = $longestDistance;
+	}
+
+	public function getLongestDistance(): float {
+		return $this->longestDistanceInNode;
+	}
+
+	public function resetLongestEdge(): void {
+		$this->longestDistanceInNode = INF;
+	}
+
+	public function resetFullyConnectedStatus(): void {
+		$this->fullyConnected = false;
+	}
+
+	/**
+	 * @return int|string|null
+	 */
+	public function getSetId() {
+		if (!$this->fullyConnected) {
+			return null;
+		}
+
+		return $this->setId;
+	}
+
+	public function isFullyConnected(): bool {
+		return $this->fullyConnected;
+	}
+
+	/**
+	 * @param array<int|string,int|string> $labelToSetId
+	 * @return int|mixed|string|null
+	 */
+	public function propagateSetChanges(array &$labelToSetId) {
+		if ($this->fullyConnected) {
+			$this->setId = $labelToSetId[$this->dataset->label(0)];
+			return $this->setId;
+		}
+
+		$labels = $this->dataset->labels();
+
+		$setId = $labelToSetId[array_pop($labels)];
+
+		foreach ($labels as $label) {
+			if ($setId !== $labelToSetId[$label]) {
+				return null;
+			}
+		}
+
+		$this->fullyConnected = true;
+		$this->setId = $setId;
+
+		return $this->setId;
+	}
+
+	/**
+	 * Terminate a branch with a dataset.
+	 *
+	 * @param \Rubix\ML\Datasets\Labeled $dataset
+	 * @param \Rubix\ML\Kernels\Distance\Distance $kernel
+	 * @return self
+	 */
+	public static function terminate(Labeled $dataset, Distance $kernel): self {
+		$center = [];
+
+		foreach ($dataset->features() as $column => $values) {
+			if ($dataset->featureType($column)->isContinuous()) {
+				$center[] = Stats::mean($values);
+			} else {
+				$center[] = argmax(array_count_values($values));
+			}
+		}
+
+		$distances = [];
+
+		foreach ($dataset->samples() as $sample) {
+			$distances[] = $kernel->compute($sample, $center);
+		}
+		$radius = max($distances) ?: 0.0;
+		return new self($dataset, $center, $radius);
+	}
+}