devfym / intelliphp

src/Regression/LinearRegression.php

<?php

namespace devfym\IntelliPHP\Regression;

use devfym\IntelliPHP\Data\DataFrame;
use devfym\IntelliPHP\Math\Validation;

class LinearRegression
{
    /**
     * @var array
     */
    private $xColumn;

    /**
     * @var array
     */
    private $yColumn;

    /**
     * @var int
     */
    private $df;

    /**
     * @var float
     */
    private $slope;

    /**
     * @var float
     */
    private $intercept;

    /**
     * @var String
     */
    private $metric;

    /**
     * LinearRegression constructor.
     */
    public function __construct()
    {
        $this->xColumn = '';

It seems like '' of type string is incompatible with the declared type array of property $xColumn.

        $this->yColumn = '';

It seems like '' of type string is incompatible with the declared type array of property $yColumn.

        $this->df = new DataFrame();

It seems like new devfym\IntelliPHP\Data\DataFrame() of type devfym\IntelliPHP\Data\DataFrame is incompatible with the declared type integer of property $df.

        $this->slope = 0;
        $this->intercept = 0;
    }

    /**
     * @param DataFrame $df
     */
    public function setTrain(DataFrame $df) : void
    {
        $this->df = $df;

It seems like $df of type devfym\IntelliPHP\Data\DataFrame is incompatible with the declared type integer of property $df.

    }

    /**
     * @param string $xColumn
     * @param string $yColumn
     * @param string $metric
     */
    public function model($xColumn = '', $yColumn = '', $metric = '') : void
    {
        $this->xColumn = $xColumn;

It seems like $xColumn of type string is incompatible with the declared type array of property $xColumn.

        $this->yColumn = $yColumn;

It seems like $yColumn of type string is incompatible with the declared type array of property $yColumn.

        $mx = $this->df->{$xColumn}->mean();
        $my = $this->df->{$yColumn}->mean();

        $this->slope = $my / $mx;

        $this->intercept = $my - ($mx * $this->slope);

        $this->metric = $metric;
    }

    /**
     * @param array $x
     * @return array
     */
    public function predict($x = []) : array
    {
        $y = [];

        foreach ($x as $p) {
            array_push($y, round(($p * $this->slope) + $this->intercept, 2));
        }

        return $y;
    }

    /**
     * @param $expected
     * @param $actual
     * @return mixed
     */
    public function validate($expected, $actual)
    {
        switch ($this->metric) {

            case 'mean_squared_error':
            case 'mse':
                return Validation::MeanSquaredError($expected, $actual);

            case 'root_mean_squared_error':
            case 'rmse':
                return Validation::RootMeanSquaredError($expected, $actual);

            default:
                return NULL;
        }
    }

    public function saveModel() : string
    {
        $model = [
            'type' => 'LinearRegression',
            'xColumn' => $this->xColumn,
            'yColumn' => $this->yColumn,
            'slope' => $this->slope,
            'intercept' => $this->intercept,
            'metric' => $this->metric
        ];

        return json_encode($model);
    }

    public function loadModel($model = '') : void
    {
        $model = json_decode($model);

        $this->xColumn = $model->xColumn;
        $this->yColumn = $model->yColumn;
        $this->slope = $model->slope;
        $this->intercept = $model->intercept;
        $this->metric = $model->metric;
    }
}