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<?php |
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namespace OCA\FaceRecognition\Helper; |
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class Euclidean |
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{ |
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/** |
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* Euclidean distance metric between two vectors |
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* |
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* The euclidean distance between two vectors (vector1, vector2) is defined as |
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* D = SQRT(SUM((vector1(i) - vector2(i))^2)) (i = 0..k) |
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* |
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* Refs: |
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* - http://mathworld.wolfram.com/EuclideanMetric.html |
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* - http://en.wikipedia.org/wiki/Euclidean_distance |
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* |
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* @param array $vector1 first vector |
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* @param array $vector2 second vector |
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* |
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* @throws Distance\NonNumericException if vectors are not numeric |
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* @throws Distance\ImcompatibleItemsException if vectors are of dissimilar size |
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* @return double The Euclidean distance between vector1 and vector2 |
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* @see _compatibleData() |
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* |
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* @assert (array(1,2,3), array(1,2,3,4)) throws Distance\IncompatibleItemsException |
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* @assert (array(2,'a',6,7), array(4,5,1,9)) throws Distance\NonNumericException |
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* @assert (array(1,2), array(3,4)) == sqrt(8) |
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* @assert (array(2,4,6,7), array(4,5,1,9)) == sqrt(4+1+25+4) |
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* |
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*/ |
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public function distance($vector1, $vector2) |
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{ |
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$n = count($vector1); |
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$sum = 0; |
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for ($i = 0; $i < $n; $i++) { |
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$sum += ($vector1[$i] - $vector2[$i]) * ($vector1[$i] - $vector2[$i]); |
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} |
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1 |
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return sqrt($sum); |
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} |
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} |
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matiasdelellis /
facerecognition
