66 lines
1.8 KiB
PHP
66 lines
1.8 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\Tests\Helper\Optimizer;
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use Phpml\Helper\Optimizer\StochasticGD;
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use PHPUnit\Framework\TestCase;
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class StochasticGDTest extends TestCase
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{
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public function testRunOptimization(): void
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{
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// 200 samples from y = -1 + 2x (i.e. theta = [-1, 2])
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$samples = [];
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$targets = [];
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for ($i = -100; $i <= 100; ++$i) {
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$x = $i / 100;
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$samples[] = [$x];
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$targets[] = -1 + 2 * $x;
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}
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$callback = function ($theta, $sample, $target) {
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$y = $theta[0] + $theta[1] * $sample[0];
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$cost = (($y - $target) ** 2) / 2;
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$grad = $y - $target;
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return [$cost, $grad];
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};
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$optimizer = new StochasticGD(1);
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$theta = $optimizer->runOptimization($samples, $targets, $callback);
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self::assertEqualsWithDelta([-1, 2], $theta, 0.1);
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}
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public function testRunOptimization2Dim(): void
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{
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// 100 samples from y = -1 + 2x0 - 3x1 (i.e. theta = [-1, 2, -3])
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$samples = [];
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$targets = [];
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for ($i = 0; $i < 100; ++$i) {
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$x0 = intval($i / 10) / 10;
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$x1 = ($i % 10) / 10;
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$samples[] = [$x0, $x1];
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$targets[] = -1 + 2 * $x0 - 3 * $x1;
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}
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$callback = function ($theta, $sample, $target) {
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$y = $theta[0] + $theta[1] * $sample[0] + $theta[2] * $sample[1];
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$cost = (($y - $target) ** 2) / 2;
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$grad = $y - $target;
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return [$cost, $grad];
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};
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$optimizer = new StochasticGD(2);
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$optimizer->setChangeThreshold(1e-6);
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$theta = $optimizer->runOptimization($samples, $targets, $callback);
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self::assertEqualsWithDelta([-1, 2, -3], $theta, 0.1);
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}
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}
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