/**
* HARMEAN
*
* Returns the harmonic mean of a data set. The harmonic mean is the reciprocal of the
* arithmetic mean of reciprocals.
*
* @param array of mixed Data Series
* @return float
*/
public static function HARMEAN()
{
// Return value
$returnValue = self::NA();
// Loop through arguments
$aArgs = PHPExcel_Calculation_Functions::flattenArray(func_get_args());
if (PHPExcel_Calculation_Functions::MIN($aArgs) < 0) {
return self::$_errorCodes['num'];
}
$aCount = 0;
foreach ($aArgs as $arg) {
// Is it a numeric value?
if (is_numeric($arg) && !is_string($arg)) {
if ($arg <= 0) {
return self::$_errorCodes['num'];
}
if (is_null($returnValue)) {
$returnValue = 1 / $arg;
} else {
$returnValue += 1 / $arg;
}
++$aCount;
}
}
// Return
if ($aCount > 0) {
return 1 / ($returnValue / $aCount);
} else {
return $returnValue;
}
}