/**
* Method to generate list of friends for 1..$upto circles.
*
* @param array An array of circles, users and their friends.
* @param integer Maximum circle number we want to build.
*
* @return null
*/
private static function _prepareCircles(&$f, $upto = self::_maximumCircleRadius)
{
$n = max(array_keys($f));
if ($n == $upto) {
return;
}
SixDegrees::_organizeArray($f);
SixDegrees::_prepareCircles($f, $upto);
return;
}
