[Summary view]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Drop out course target.
  19   *
  20   * @package   core_course
  21   * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
  22   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  namespace core_course\analytics\target;
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  require_once($CFG->dirroot . '/course/lib.php');
  30  require_once($CFG->dirroot . '/lib/gradelib.php');
  31  require_once($CFG->dirroot . '/lib/completionlib.php');
  32  require_once($CFG->dirroot . '/completion/completion_completion.php');
  33  
  34  /**
  35   * Drop out course target.
  36   *
  37   * @package   core_course
  38   * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
  39   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  40   */
  41  class course_dropout extends course_enrolments {
  42  
  43      /**
  44       * Returns the name.
  45       *
  46       * If there is a corresponding '_help' string this will be shown as well.
  47       *
  48       * @return \lang_string
  49       */
  50      public static function get_name() : \lang_string {
  51          return new \lang_string('target:coursedropout', 'course');
  52      }
  53  
  54      /**
  55       * classes_description
  56       *
  57       * @return string[]
  58       */
  59      protected static function classes_description() {
  60          return array(
  61              get_string('targetlabelstudentdropoutno', 'course'),
  62              get_string('targetlabelstudentdropoutyes', 'course')
  63          );
  64      }
  65  
  66      /**
  67       * Discards courses that are not yet ready to be used for training or prediction.
  68       *
  69       * @param \core_analytics\analysable $course
  70       * @param bool $fortraining
  71       * @return true|string
  72       */
  73      public function is_valid_analysable(\core_analytics\analysable $course, $fortraining = true) {
  74          global $DB;
  75  
  76          $isvalid = parent::is_valid_analysable($course, $fortraining);
  77  
  78          if (is_string($isvalid)) {
  79              return $isvalid;
  80          }
  81  
  82          if ($fortraining) {
  83              // Not a valid target for training if there are not enough course accesses between the course start and end dates.
  84              $params = array('courseid' => $course->get_id(), 'anonymous' => 0, 'start' => $course->get_start(),
  85                  'end' => $course->get_end());
  86              list($studentssql, $studentparams) = $DB->get_in_or_equal($this->students, SQL_PARAMS_NAMED);
  87              // Using anonymous to use the db index, not filtering by timecreated to speed it up.
  88              $select = 'courseid = :courseid AND anonymous = :anonymous AND timecreated > :start AND timecreated < :end ' .
  89                  'AND userid ' . $studentssql;
  90  
  91              if (!$logstore = \core_analytics\manager::get_analytics_logstore()) {
  92                  throw new \coding_exception('No available log stores');
  93              }
  94              $nlogs = $logstore->get_events_select_count($select, array_merge($params, $studentparams));
  95  
  96              // At least a minimum of students activity.
  97              $nstudents = count($this->students);
  98              if ($nlogs / $nstudents < 10) {
  99                  return get_string('nocourseactivity', 'course');
 100              }
 101          }
 102  
 103          return true;
 104      }
 105  
 106      /**
 107       * calculate_sample
 108       *
 109       * The meaning of a drop out changes depending on the settings enabled in the course. Following these priorities order:
 110       * 1.- Course completion
 111       * 2.- No logs during the last quarter of the course
 112       *
 113       * @param int $sampleid
 114       * @param \core_analytics\analysable $course
 115       * @param int $starttime
 116       * @param int $endtime
 117       * @return float|null 0 -> not at risk, 1 -> at risk
 118       */
 119      protected function calculate_sample($sampleid, \core_analytics\analysable $course, $starttime = false, $endtime = false) {
 120  
 121          if (!$this->enrolment_active_during_analysis_time($sampleid, $starttime, $endtime)) {
 122              // We should not use this sample as the analysis results could be misleading.
 123              return null;
 124          }
 125  
 126          $userenrol = $this->retrieve('user_enrolments', $sampleid);
 127  
 128          // We use completion as a success metric only when it is enabled.
 129          $completion = new \completion_info($course->get_course_data());
 130          if ($completion->is_enabled() && $completion->has_criteria()) {
 131              $ccompletion = new \completion_completion(array('userid' => $userenrol->userid, 'course' => $course->get_id()));
 132              if ($ccompletion->is_complete()) {
 133                  return 0;
 134              } else {
 135                  return 1;
 136              }
 137          }
 138  
 139          if (!$logstore = \core_analytics\manager::get_analytics_logstore()) {
 140              throw new \coding_exception('No available log stores');
 141          }
 142  
 143          // No logs during the last quarter of the course.
 144          $courseduration = $course->get_end() - $course->get_start();
 145          $limit = intval($course->get_end() - ($courseduration / 4));
 146          $select = "courseid = :courseid AND userid = :userid AND timecreated > :limit";
 147          $params = array('userid' => $userenrol->userid, 'courseid' => $course->get_id(), 'limit' => $limit);
 148          $nlogs = $logstore->get_events_select_count($select, $params);
 149          if ($nlogs == 0) {
 150              return 1;
 151          }
 152          return 0;
 153      }
 154  }