77 lines
1.5 KiB
PHP
77 lines
1.5 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\NeuralNetwork\Node;
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use Phpml\NeuralNetwork\ActivationFunction;
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use Phpml\NeuralNetwork\ActivationFunction\Sigmoid;
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use Phpml\NeuralNetwork\Node;
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use Phpml\NeuralNetwork\Node\Neuron\Synapse;
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class Neuron implements Node
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{
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/**
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* @var Synapse[]
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*/
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protected $synapses = [];
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/**
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* @var ActivationFunction
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*/
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protected $activationFunction;
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/**
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* @var float
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*/
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protected $output = 0.0;
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/**
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* @var float
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*/
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protected $z = 0.0;
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public function __construct(?ActivationFunction $activationFunction = null)
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{
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$this->activationFunction = $activationFunction ?? new Sigmoid();
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}
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public function addSynapse(Synapse $synapse): void
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{
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$this->synapses[] = $synapse;
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}
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/**
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* @return Synapse[]
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*/
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public function getSynapses(): array
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{
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return $this->synapses;
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}
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public function getOutput(): float
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{
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if ($this->output === 0.0) {
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$this->z = 0;
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foreach ($this->synapses as $synapse) {
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$this->z += $synapse->getOutput();
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}
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$this->output = $this->activationFunction->compute($this->z);
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}
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return $this->output;
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}
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public function getDerivative(): float
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{
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return $this->activationFunction->differentiate($this->z, $this->output);
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}
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public function reset(): void
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{
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$this->output = 0.0;
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$this->z = 0.0;
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}
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}
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