40 lines
670 B
PHP
40 lines
670 B
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\Math\Kernel;
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use Phpml\Math\Kernel;
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use Phpml\Math\Product;
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class RBF implements Kernel
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{
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/**
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* @var float
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*/
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private $gamma;
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/**
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* @param float $gamma
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*/
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public function __construct(float $gamma)
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{
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$this->gamma = $gamma;
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}
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/**
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* @param float $a
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* @param float $b
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*
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* @return float
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*/
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public function compute($a, $b)
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{
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$score = 2 * Product::scalar($a, $b);
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$squares = Product::scalar($a, $a) + Product::scalar($b, $b);
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$result = exp(-$this->gamma * ($squares - $score));
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return $result;
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}
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}
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