/**
* Returns the ID of the archived subperiods.
*
* @return array Array of the idArchive of the subperiods
*/
protected function loadSubperiodsArchive()
{
$periods = array();
// we first compute every subperiod of the archive
foreach ($this->period->getSubperiods() as $period) {
$archivePeriod = new Piwik_Archive_Single();
$archivePeriod->setSite($this->site);
$archivePeriod->setPeriod($period);
$archivePeriod->prepareArchive();
$periods[] = $archivePeriod;
}
return $periods;
}