Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Question statistics calculations class. Used in the quiz statistics report.

 *

 * @package    core_question

 * @copyright  2018 Ryan Wyllie <ryan@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

namespace core_question\statistics\questions;

defined('MOODLE_INTERNAL') || die();

require_once($CFG->dirroot . '/question/engine/lib.php');

/**

 * Class calculated_question_summary

 *

 * This class is used to indicate the statistics for a random question slot should

 * be rendered with a link to a summary of the displayed questions.

 *

 * It's used in the limited view of the statistics calculation in lieu of adding

 * the stats for each subquestion individually.

 *

 * @copyright 2018 Ryan Wyllie <ryan@moodle.com>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class calculated_question_summary extends calculated {

    /**

     * @var int only set immediately before display in the table. The order of display in the table.

     */

    public $subqdisplayorder;

    /**

     * @var calculated[] The instances storing the calculated stats of the questions that are being summarised.

     */

    protected $subqstats;

    /**

     * calculated_question_summary constructor.

     *

     * @param \stdClass $question

     * @param int $slot

     * @param calculated[] $subqstats The instances of the calculated stats of the questions that are being summarised.

     */

    public function __construct($question, $slot, $subqstats) {

        parent::__construct($question, $slot);

        $this->subqstats = $subqstats;

        $this->subquestions = implode(',', array_column($subqstats, 'questionid'));

    }

    /**

     * This is a summary stat so never breakdown by variant.

     *

     * @return bool

     */

    public function break_down_by_variant() {

        return false;

    }

    /**

     * Returns the minimum and maximum values of the given attribute in the summarised calculated stats.

     *

     * @param string $attribute The attribute that we are looking for its extremums.

     * @return array An array of [min,max]

     */

    public function get_min_max_of($attribute) {

        $getmethod = 'get_min_max_of_' . $attribute;

        if (method_exists($this, $getmethod)) {

            return $this->$getmethod();

        } else {

            $min = $max = null;

            $set = false;

            // We cannot simply use min or max functions because, in theory, some attributes might be non-scalar.

            foreach (array_column($this->subqstats, $attribute) as $value) {

                if (is_scalar($value) || is_null($value)) {

                    if (!$set) {    // It is not good enough to check if (!isset($min)),

                                    // because $min might have been set to null in an earlier iteration.

                        $min = $value;

                        $max = $value;

                        $set = true;

                    }

                    $min  = $this->min($min, $value);

                    $max  = $this->max($max, $value);

                }

            }

            return [$min, $max];

        }

    }

    /**

     * Returns the minimum and maximum values of the standard deviation in the summarised calculated stats.

     * @return array An array of [min,max]

     */

    protected function get_min_max_of_sd() {

        $min = $max = null;

        $set = false;

        foreach ($this->subqstats as $subqstat) {

            if (isset($subqstat->sd) && $subqstat->maxmark > \question_utils::MARK_TOLERANCE) {

                $value = $subqstat->sd / $subqstat->maxmark;

            } else {

                $value = null;

            }

            if (!$set) {    // It is not good enough to check if (!isset($min)),

                            // because $min might have been set to null in an earlier iteration.

                $min = $value;

                $max = $value;

                $set = true;

            }

            $min = $this->min($min, $value);

            $max = $this->max($max, $value);

        }

        return [$min, $max];

    }

    /**

     * Find higher value.

     * A zero value is almost considered equal to zero in comparisons. The only difference is that when being compared to zero,

     * zero is higher than null.

     *

     * @param float|null $value1

     * @param float|null $value2

     * @return float|null

     */

    protected function max(float $value1 = null, float $value2 = null) {

        $temp1 = $value1 ?: 0;

        $temp2 = $value2 ?: 0;

        $tempmax = max($temp1, $temp2);

        if (!$tempmax && $value1 !== 0 && $value2 !== 0) {

            $max = null;

        } else {

            $max = $tempmax;

        }

        return $max;

    }

    /**

     * Find lower value.

     * A zero value is almost considered equal to zero in comparisons. The only difference is that when being compared to zero,

     * zero is lower than null.

     *

     * @param float|null $value1

     * @param float|null $value2

     * @return mixed|null

     */

    protected function min(float $value1 = null, float $value2 = null) {

        $temp1 = $value1 ?: 0;

        $temp2 = $value2 ?: 0;

        $tempmin = min($temp1, $temp2);

        if (!$tempmin && $value1 !== 0 && $value2 !== 0) {

            $min = null;

        } else {

            $min = $tempmin;

        }

        return $min;

    }

}