Current Path : C:/xampp/htdocs/moodle/analytics/classes/local/time_splitting/ |
Current File : C:/xampp/htdocs/moodle/analytics/classes/local/time_splitting/periodic.php |
<?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/>. /** * Time splitting method that generates predictions regularly. * * @package core_analytics * @copyright 2019 David Monllao {@link http://www.davidmonllao.com} * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ namespace core_analytics\local\time_splitting; defined('MOODLE_INTERNAL') || die(); /** * Time splitting method that generates predictions periodically. * * @package core_analytics * @copyright 2019 David Monllao {@link http://www.davidmonllao.com} * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ abstract class periodic extends base { /** * The periodicity of the predictions / training data generation. * * @return \DateInterval */ abstract protected function periodicity(); /** * Gets the next range with start on the provided time. * * @param \DateTimeImmutable $time * @return array */ abstract protected function get_next_range(\DateTimeImmutable $time); /** * Get the start of the first time range. * * @return int A timestamp. */ abstract protected function get_first_start(); /** * Returns whether the analysable can be processed by this time splitting method or not. * * @param \core_analytics\analysable $analysable * @return bool */ public function is_valid_analysable(\core_analytics\analysable $analysable) { if (!$analysable->get_start()) { return false; } return true; } /** * define_ranges * * @return array */ protected function define_ranges() { $periodicity = $this->periodicity(); if ($this->analysable->get_end()) { $end = (new \DateTimeImmutable())->setTimestamp($this->analysable->get_end()); } $nexttime = (new \DateTimeImmutable())->setTimestamp($this->get_first_start()); $now = new \DateTimeImmutable('now', \core_date::get_server_timezone_object()); $range = $this->get_next_range($nexttime); if (!$range) { $nexttime = $nexttime->add($periodicity); $range = $this->get_next_range($nexttime); if (!$range) { throw new \coding_exception('The get_next_range implementation is broken. The difference between two consecutive ranges can not be more than the periodicity.'); } } $ranges = []; $endreached = false; while (($this->ready_to_predict($range) || $this->ready_to_train($range)) && !$endreached) { $ranges[] = $range; $nexttime = $nexttime->add($periodicity); $range = $this->get_next_range($nexttime); $endreached = (!empty($end) && $nexttime > $end); } if ($ranges && !$endreached) { // If this analysable is not finished we adjust the start and end of the last element in $ranges // so that it ends in time().The reason is that the start of these ranges is based on the analysable // start and the end is calculated based on the start. This is to prevent the same issue we had in MDL-65348. // // An example of the situation we want to avoid is: // A course started on a Monday, in 2015. It has no end date. Now the system is upgraded to Moodle 3.8, which // includes this code. This happens on Wednesday. Periodic ranges (e.g. weekly) will be calculated from a Monday // so the data provided by the time-splitting method would be from Monday to Monday, when we really want to // provide data from Wednesday to the past Wednesday. $ranges = $this->update_last_range($ranges); } return $ranges; } /** * Overwritten as all generated rows are comparable. * * @return bool */ public function include_range_info_in_training_data() { return false; } /** * Overwritting as the last range may be for prediction. * * @return array */ public function get_training_ranges() { // Cloning the array. $trainingranges = $this->ranges; foreach ($trainingranges as $rangeindex => $range) { if (!$this->ready_to_train($range)) { unset($trainingranges[$rangeindex]); } } return $trainingranges; } /** * Allows child classes to update the last range provided. * * @param array $ranges * @return array */ protected function update_last_range(array $ranges) { return $ranges; } }