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<?php |
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/** |
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* This file is part of PHP K-Means |
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* |
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* Copyright (c) 2014 Benjamin Delespierre |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is furnished |
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* to do so, subject to the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in all |
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* copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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* THE SOFTWARE. |
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*/ |
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namespace KMeans; |
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use KMeans\Algorithms\CallbackDistance; |
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use KMeans\Algorithms\EuclidianDistance; |
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use KMeans\Interfaces\DistanceAlgorithmInterface; |
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use KMeans\Interfaces\SpaceInterface; |
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class Space extends \SplObjectStorage implements SpaceInterface |
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{ |
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protected $dimention; |
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protected $distanceAlgo; |
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protected static $rng = 'mt_rand'; |
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public function __construct($dimention) |
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{ |
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if ($dimention < 1) { |
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throw new \LogicException("a space dimention cannot be null or negative"); |
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} |
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$this->dimention = $dimention; |
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$this->setDistanceAlgorithm(new EuclidianDistance()); |
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} |
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public static function setRng(callable $fn): void |
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{ |
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static::$rng = $fn; |
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} |
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public function setDistanceAlgorithm($algo): void |
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{ |
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if (is_callable($algo) && ! $algo instanceof DistanceAlgorithmInterface) { |
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$algo = new CallbackDistance($algo); |
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} |
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if (! $algo instanceof DistanceAlgorithmInterface) { |
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throw new \RuntimeException( |
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"distance algorithm must implement KMeans\Interfaces\DistanceAlgorithmInterface" |
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); |
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} |
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$this->distanceAlgo = $algo; |
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foreach ($this as $point) { |
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$point->setDistanceAlgorithm($algo); |
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} |
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} |
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public function toArray(): array |
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{ |
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$points = []; |
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foreach ($this as $point) { |
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$points[] = $point->toArray(); |
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} |
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return ['points' => $points]; |
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} |
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public function newPoint(array $coordinates): Point |
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{ |
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if (count($coordinates) != $this->dimention) { |
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throw new \LogicException("(" . implode(',', $coordinates) . ") is not a point of this space"); |
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} |
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return new Point($this, $coordinates, $this->distanceAlgo); |
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} |
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public function addPoint(array $coordinates, $data = null): Point |
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{ |
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$this->attach($point = $this->newPoint($coordinates), $data); |
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return $point; |
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} |
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public function attach($point, $data = null): void |
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{ |
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if (!$point instanceof Point) { |
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throw new \InvalidArgumentException("can only attach points to spaces"); |
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} |
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parent::attach($point, $data); |
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} |
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public function getDimention(): int |
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{ |
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return $this->dimention; |
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} |
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public function getBoundaries(): array |
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{ |
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if (!count($this)) { |
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return []; |
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} |
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$min = $this->newPoint(array_fill(0, $this->dimention, null)); |
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$max = $this->newPoint(array_fill(0, $this->dimention, null)); |
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foreach ($this as $point) { |
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for ($n = 0; $n < $this->dimention; $n++) { |
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View Code Duplication |
if ($min[$n] === null || $min[$n] > $point[$n]) { |
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$min[$n] = $point[$n]; |
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} |
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View Code Duplication |
if ($max[$n] === null || $max[$n] < $point[$n]) { |
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$max[$n] = $point[$n]; |
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} |
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} |
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} |
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return [$min, $max]; |
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} |
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public function getRandomPoint(Point $min, Point $max): Point |
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{ |
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$point = $this->newPoint(array_fill(0, $this->dimention, null)); |
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$rng = static::$rng; |
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for ($n = 0; $n < $this->dimention; $n++) { |
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$point[$n] = $rng($min[$n], $max[$n]); |
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} |
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return $point; |
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} |
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public function solve(int $nbClusters, callable $iterationCallback = null): array |
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{ |
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// initialize K clusters |
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$clusters = $this->initializeClusters($nbClusters); |
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// there's only one cluster, clusterization has no meaning |
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if (count($clusters) == 1) { |
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return $clusters; |
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} |
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// until convergence is reached |
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do { |
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if ($iterationCallback) { |
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$iterationCallback($this, $clusters); |
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} |
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} while ($this->iterate($clusters)); |
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// clustering is done. |
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return $clusters; |
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} |
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protected function initializeClusters(int $nbClusters): array |
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{ |
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if ($nbClusters <= 0) { |
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throw new \InvalidArgumentException("invalid clusters number"); |
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} |
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$clusters = []; |
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// get the space boundaries to avoid placing clusters centroid too far from points |
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list($min, $max) = $this->getBoundaries(); |
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// initialize N clusters with a random point within space boundaries |
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for ($n = 0; $n < $nbClusters; $n++) { |
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$clusters[] = new Cluster($this, $this->getRandomPoint($min, $max)->getCoordinates()); |
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} |
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// assign all points to the first cluster |
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$clusters[0]->attachAll($this); |
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return $clusters; |
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} |
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protected function iterate(array $clusters): bool |
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{ |
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$continue = false; |
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// migration storages |
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$attach = new \SplObjectStorage(); |
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$detach = new \SplObjectStorage(); |
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// calculate proximity amongst points and clusters |
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foreach ($clusters as $cluster) { |
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foreach ($cluster as $point) { |
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// find the closest cluster |
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$closest = $point->getClosest($clusters); |
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// move the point from its old cluster to its closest |
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if ($closest !== $cluster) { |
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if (! isset($attach[$closest])) { |
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$attach[$closest] = new \SplObjectStorage(); |
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} |
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if (! isset($detach[$cluster])) { |
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$detach[$cluster] = new \SplObjectStorage(); |
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} |
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$attach[$closest]->attach($point); |
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$detach[$cluster]->attach($point); |
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$continue = true; |
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} |
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} |
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} |
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// perform points migrations |
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foreach ($attach as $cluster) { |
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$cluster->attachAll($attach[$cluster]); |
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} |
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foreach ($detach as $cluster) { |
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$cluster->detachAll($detach[$cluster]); |
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} |
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// update all cluster's centroids |
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foreach ($clusters as $cluster) { |
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$cluster->updateCentroid(); |
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} |
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return $continue; |
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} |
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} |
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Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property.
Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property..