PowerCorrelationAnalyzer.php

<?php

namespace App\Application\Analytics;

use App\Application\Math\PearsonCorrelation;
use App\Application\Math\Result\PearsonCorrelationResult;
use App\Domain\PowerStation;
use Doctrine\Common\Collections\ArrayCollection;
use MathPHP\Exception\MathException;
use MathPHP\Statistics\Multivariate\PCA;
use MathPHP\LinearAlgebra\MatrixFactory;
use Rubix\ML\Datasets\Unlabeled;
use Rubix\ML\Extractors\ColumnPicker;
use Rubix\ML\Transformers\ZScaleStandardizer;

class PowerCorrelationAnalyzer
{
    /**
     * @param ArrayCollection<int, PowerStation> $dataset
     * @param string[]                           $variables
     *
     * @return ArrayCollection<string, PearsonCorrelationResult>
     *
     * @throws MathException
     */
    public static function checkCorrelation(
        ArrayCollection $dataset,
        array $variables = PowerStation::VARIABLES,
    ): ArrayCollection {
        $correlations = new ArrayCollection();
        $powers = $dataset->map(fn (PowerStation $powerStation) => $powerStation->power)->toArray();

        foreach ($variables as $variable) {
            $correlations->set($variable, PearsonCorrelation::calculate(
                $dataset->map(fn (PowerStation $powerStation) => $powerStation->{$variable})->toArray(),
                $powers,
            ));
        }

        return $correlations;
    }

    /**
     * @param ArrayCollection<int, PowerStation> $dataset
     * @param string[]                           $variables
     *
     * @throws MathException
     */
    public static function analysisPCA(
        ArrayCollection $dataset,
        array $variables = PowerStation::VARIABLES,
    ): PCA {
        $normalized = Unlabeled::fromIterator(new ColumnPicker(
            json_decode(json_encode($dataset->toArray()), true),
            $variables,
        ))->apply(new ZScaleStandardizer(true));

        $matrix = MatrixFactory::create($normalized->samples());

        // @phpstan-ignore-next-line
        return new PCA($matrix, true, true);
    }
}