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Differences Between: [Versions 310 and 402] [Versions 311 and 402] [Versions 39 and 402] [Versions 402 and 403]

   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   * This file contains the code to analyse all the responses to a particular question.
  19   *
  20   * @package    core_question
  21   * @copyright  2014 Open University
  22   * @author     Jamie Pratt <me@jamiep.org>
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  namespace core_question\statistics\responses;
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  /**
  30   * This class can compute, store and cache the analysis of the responses to a particular question.
  31   *
  32   * @package    core_question
  33   * @copyright  2014 The Open University
  34   * @author     James Pratt me@jamiep.org
  35   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  36   */
  37  class analyser {
  38      /**
  39       * @var int When analysing responses and breaking down the count of responses per try, how many columns should we break down
  40       * tries into? This is set to 5 columns, any response in a try more than try 5 will be counted in the fifth column.
  41       */
  42      const MAX_TRY_COUNTED = 5;
  43  
  44      /** @var int No longer used. Previously the time after which statistics are automatically recomputed. */
  45      const TIME_TO_CACHE = 900; // 15 minutes.
  46  
  47      /** @var object full question data from db. */
  48      protected $questiondata;
  49  
  50      /**
  51       * @var analysis_for_question|analysis_for_question_all_tries
  52       */
  53      public $analysis;
  54  
  55      /**
  56       * @var int used during calculations, so all results are stored with the same timestamp.
  57       */
  58      protected $calculationtime;
  59  
  60      /**
  61       * @var array Two index array first index is unique string for each sub question part, the second string index is the 'class'
  62       * that sub-question part can be classified into.
  63       *
  64       * This is the return value from {@link \question_type::get_possible_responses()} see that method for fuller documentation.
  65       */
  66      public $responseclasses = array();
  67  
  68      /**
  69       * @var bool whether to break down response analysis by variant. This only applies to questions that have variants and is
  70       *           used to suppress the break down of analysis by variant when there are going to be very many variants.
  71       */
  72      protected $breakdownbyvariant;
  73  
  74      /**
  75       * Create a new instance of this class for holding/computing the statistics
  76       * for a particular question.
  77       *
  78       * @param object $questiondata the full question data from the database defining this question.
  79       * @param string $whichtries   which tries to analyse.
  80       */
  81      public function __construct($questiondata, $whichtries = \question_attempt::LAST_TRY) {
  82          $this->questiondata = $questiondata;
  83          $qtypeobj = \question_bank::get_qtype($this->questiondata->qtype);
  84          if ($whichtries != \question_attempt::ALL_TRIES) {
  85              $this->analysis = new analysis_for_question($qtypeobj->get_possible_responses($this->questiondata));
  86          } else {
  87              $this->analysis = new analysis_for_question_all_tries($qtypeobj->get_possible_responses($this->questiondata));
  88          }
  89  
  90          $this->breakdownbyvariant = $qtypeobj->break_down_stats_and_response_analysis_by_variant($this->questiondata);
  91      }
  92  
  93      /**
  94       * Does the computed analysis have sub parts?
  95       *
  96       * @return bool whether this analysis has more than one subpart.
  97       */
  98      public function has_subparts() {
  99          return count($this->responseclasses) > 1;
 100      }
 101  
 102      /**
 103       * Does the computed analysis's sub parts have classes?
 104       *
 105       * @return bool whether this analysis has (a subpart with) more than one response class.
 106       */
 107      public function has_response_classes() {
 108          foreach ($this->responseclasses as $partclasses) {
 109              if (count($partclasses) > 1) {
 110                  return true;
 111              }
 112          }
 113          return false;
 114      }
 115  
 116      /**
 117       * Analyse all the response data for all the specified attempts at this question.
 118       *
 119       * @param \qubaid_condition $qubaids which attempts to consider.
 120       * @param string $whichtries         which tries to analyse. Will be one of
 121       *                                   \question_attempt::FIRST_TRY, LAST_TRY or ALL_TRIES.
 122       * @return analysis_for_question
 123       */
 124      public function calculate($qubaids, $whichtries = \question_attempt::LAST_TRY) {
 125          $this->calculationtime = time();
 126          // Load data.
 127          $dm = new \question_engine_data_mapper();
 128          $questionattempts = $dm->load_attempts_at_question($this->questiondata->id, $qubaids);
 129  
 130          // Analyse it.
 131          foreach ($questionattempts as $qa) {
 132              $responseparts = $qa->classify_response($whichtries);
 133              if ($this->breakdownbyvariant) {
 134                  $this->analysis->count_response_parts($qa->get_variant(), $responseparts);
 135              } else {
 136                  $this->analysis->count_response_parts(1, $responseparts);
 137              }
 138  
 139          }
 140          $this->analysis->cache($qubaids, $whichtries, $this->questiondata->id, $this->calculationtime);
 141          return $this->analysis;
 142      }
 143  
 144      /**
 145       * Retrieve the computed response analysis from the question_response_analysis table.
 146       *
 147       * @param \qubaid_condition $qubaids    load the analysis of which question usages?
 148       * @param string            $whichtries load the analysis of which tries?
 149       * @return analysis_for_question|boolean analysis or false if no cached analysis found.
 150       */
 151      public function load_cached($qubaids, $whichtries) {
 152          global $DB;
 153  
 154          $timemodified = self::get_last_analysed_time($qubaids, $whichtries);
 155          // Variable name 'analyses' is the plural of 'analysis'.
 156          $responseanalyses = $DB->get_records('question_response_analysis',
 157                  ['hashcode' => $qubaids->get_hash_code(), 'whichtries' => $whichtries,
 158                          'questionid' => $this->questiondata->id, 'timemodified' => $timemodified]);
 159          if (!$responseanalyses) {
 160              return false;
 161          }
 162  
 163          $analysisids = [];
 164          foreach ($responseanalyses as $responseanalysis) {
 165              $analysisforsubpart = $this->analysis->get_analysis_for_subpart($responseanalysis->variant, $responseanalysis->subqid);
 166              $class = $analysisforsubpart->get_response_class($responseanalysis->aid);
 167              $class->add_response($responseanalysis->response, $responseanalysis->credit);
 168              $analysisids[] = $responseanalysis->id;
 169          }
 170          [$sql, $params] = $DB->get_in_or_equal($analysisids);
 171          $counts = $DB->get_records_select('question_response_count', "analysisid {$sql}", $params);
 172          foreach ($counts as $count) {
 173              $responseanalysis = $responseanalyses[$count->analysisid];
 174              $analysisforsubpart = $this->analysis->get_analysis_for_subpart($responseanalysis->variant, $responseanalysis->subqid);
 175              $class = $analysisforsubpart->get_response_class($responseanalysis->aid);
 176              $class->set_response_count($responseanalysis->response, $count->try, $count->rcount);
 177  
 178          }
 179          return $this->analysis;
 180      }
 181  
 182  
 183      /**
 184       * Find time of non-expired analysis in the database.
 185       *
 186       * @param \qubaid_condition $qubaids    check for the analysis of which question usages?
 187       * @param string            $whichtries check for the analysis of which tries?
 188       * @return integer|boolean Time of cached record that matches this qubaid_condition or false if none found.
 189       */
 190      public function get_last_analysed_time($qubaids, $whichtries) {
 191          global $DB;
 192          return $DB->get_field('question_response_analysis', 'MAX(timemodified)',
 193                  ['hashcode' => $qubaids->get_hash_code(), 'whichtries' => $whichtries,
 194                          'questionid' => $this->questiondata->id]);
 195      }
 196  }