code: public function process()
      {
          $orderedTasks = $this->_tasks;
          usort($orderedTasks, function($a, $b) {
              return $a->duration() > $b->duration() ? 1 : -1;
          });
  
          $this->_ranking = $orderedTasks;
  
          $matrix = [];
          foreach($this->_ranking as $task1) {
              $name1 = $task1->name();
              $matrix[$name1] = [];
  
              foreach($this->_ranking as $task2) {
                  $name2 = $task2->name();
                  $percent = intval(round($task1->duration() / $task2->duration() * 100));
                  $matrix[$name1][$name2] = $percent;
              }
          }
          $this->_matrix = $matrix;
          return $this;
      }
docs: Builds the matrix result.
  
  @return self